Add string functions: concat(), concat_ws(), left(), right(), and reverse().
Pavel Stehule, reviewed by me.
This commit is contained in:
Itagaki Takahiro
parent
b9defe0405
commit
49b27ab551
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.529 2010/08/17 04:37:20 petere Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.530 2010/08/24 06:30:43 itagaki Exp $ -->
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<chapter id="functions">
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<title>Functions and Operators</title>
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@ -1250,6 +1250,12 @@
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<indexterm>
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<primary>chr</primary>
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</indexterm>
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<indexterm>
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<primary>concat</primary>
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</indexterm>
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<indexterm>
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<primary>concat_ws</primary>
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</indexterm>
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<indexterm>
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<primary>convert</primary>
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</indexterm>
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@ -1268,6 +1274,9 @@
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<indexterm>
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<primary>initcap</primary>
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</indexterm>
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<indexterm>
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<primary>left</primary>
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</indexterm>
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<indexterm>
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<primary>lpad</primary>
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</indexterm>
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@ -1295,6 +1304,12 @@
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<indexterm>
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<primary>replace</primary>
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</indexterm>
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<indexterm>
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<primary>reverse</primary>
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</indexterm>
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<indexterm>
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<primary>right</primary>
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</indexterm>
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<indexterm>
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<primary>rpad</primary>
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</indexterm>
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@ -1374,6 +1389,34 @@
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<entry><literal>A</literal></entry>
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</row>
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<row>
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<entry>
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<literal><function>concat</function>(<parameter>str</parameter> <type>"any"</type>
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[, <parameter>str</parameter> <type>"any"</type> [, ...] ])</literal>
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</entry>
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<entry><type>text</type></entry>
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<entry>
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Concatenate all arguments. NULL arguments are ignored.
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</entry>
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<entry><literal>concat('abcde', 2, NULL, 22)</literal></entry>
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<entry><literal>abcde222</literal></entry>
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</row>
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<row>
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<entry>
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<literal><function>concat_ws</function>(<parameter>sep</parameter> <type>text</type>,
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<parameter>str</parameter> <type>"any"</type>
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[, <parameter>str</parameter> <type>"any"</type> [, ...] ])</literal>
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</entry>
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<entry><type>text</type></entry>
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<entry>
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Concatenate all but first arguments with separators. The first
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parameter is used as a separator. NULL arguments are ignored.
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</entry>
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<entry><literal>concat_ws(',', 'abcde', 2, NULL, 22)</literal></entry>
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<entry><literal>abcde,2,22</literal></entry>
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</row>
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<row>
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<entry>
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<literal><function>convert</function>(<parameter>string</parameter> <type>bytea</type>,
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@ -1465,6 +1508,20 @@
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<entry><literal>Hi Thomas</literal></entry>
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</row>
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<row>
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<entry>
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<literal><function>left</function>(<parameter>str</parameter> <type>text</type>,
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<parameter>n</parameter> <type>int</type>)</literal>
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</entry>
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<entry><type>text</type></entry>
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<entry>
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Return first <replaceable>n</> characters in the string. When <replaceable>n</>
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is negative, return all but last |<replaceable>n</>| characters.
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</entry>
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<entry><literal>left('abcde', 2)</literal></entry>
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<entry><literal>ab</literal></entry>
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</row>
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<row>
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<entry><literal><function>length</function>(<parameter>string</parameter>)</literal></entry>
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<entry><type>int</type></entry>
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@ -1678,6 +1735,32 @@
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<entry><literal>abXXefabXXef</literal></entry>
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</row>
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<row>
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<entry>
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<literal><function>reverse</function>(<parameter>str</parameter>)</literal>
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</entry>
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<entry><type>text</type></entry>
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<entry>
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Return reversed string.
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</entry>
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<entry><literal>reverse('abcde')</literal></entry>
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<entry><literal>edcba</literal></entry>
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</row>
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<row>
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<entry>
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<literal><function>right</function>(<parameter>str</parameter> <type>text</type>,
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<parameter>n</parameter> <type>int</type>)</literal>
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</entry>
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<entry><type>text</type></entry>
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<entry>
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Return last <replaceable>n</> characters in the string. When <replaceable>n</>
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is negative, return all but first |<replaceable>n</>| characters.
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</entry>
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<entry><literal>right('abcde', 2)</literal></entry>
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<entry><literal>de</literal></entry>
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</row>
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<row>
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<entry>
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<literal><function>rpad</function>(<parameter>string</parameter> <type>text</type>,
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.179 2010/08/10 21:51:00 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.180 2010/08/24 06:30:43 itagaki Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -3556,3 +3556,149 @@ string_agg_finalfn(PG_FUNCTION_ARGS)
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else
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PG_RETURN_NULL();
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}
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static text *
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concat_internal(const char *sepstr, int seplen, int argidx, FunctionCallInfo fcinfo)
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{
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StringInfoData str;
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text *result;
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int i;
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initStringInfo(&str);
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for (i = argidx; i < PG_NARGS(); i++)
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{
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if (!PG_ARGISNULL(i))
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{
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Oid valtype;
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Datum value;
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Oid typOutput;
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bool typIsVarlena;
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if (i > argidx)
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appendBinaryStringInfo(&str, sepstr, seplen);
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/* append n-th value */
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value = PG_GETARG_DATUM(i);
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valtype = get_fn_expr_argtype(fcinfo->flinfo, i);
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getTypeOutputInfo(valtype, &typOutput, &typIsVarlena);
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appendStringInfoString(&str,
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OidOutputFunctionCall(typOutput, value));
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}
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}
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result = cstring_to_text_with_len(str.data, str.len);
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pfree(str.data);
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return result;
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}
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/*
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* Concatenate all arguments. NULL arguments are ignored.
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*/
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Datum
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text_concat(PG_FUNCTION_ARGS)
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{
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PG_RETURN_TEXT_P(concat_internal(NULL, 0, 0, fcinfo));
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}
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/*
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* Concatenate all but first argument values with separators. The first
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* parameter is used as a separator. NULL arguments are ignored.
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*/
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Datum
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text_concat_ws(PG_FUNCTION_ARGS)
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{
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text *sep;
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/* return NULL when separator is NULL */
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if (PG_ARGISNULL(0))
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PG_RETURN_NULL();
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sep = PG_GETARG_TEXT_PP(0);
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PG_RETURN_TEXT_P(concat_internal(
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VARDATA_ANY(sep), VARSIZE_ANY_EXHDR(sep), 1, fcinfo));
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}
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/*
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* Return first n characters in the string. When n is negative,
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* return all but last |n| characters.
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*/
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Datum
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text_left(PG_FUNCTION_ARGS)
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{
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text *str = PG_GETARG_TEXT_PP(0);
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const char *p = VARDATA_ANY(str);
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int len = VARSIZE_ANY_EXHDR(str);
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int n = PG_GETARG_INT32(1);
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int rlen;
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if (n < 0)
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n = pg_mbstrlen_with_len(p, len) + n;
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rlen = pg_mbcharcliplen(p, len, n);
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PG_RETURN_TEXT_P(cstring_to_text_with_len(p, rlen));
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}
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/*
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* Return last n characters in the string. When n is negative,
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* return all but first |n| characters.
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*/
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Datum
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text_right(PG_FUNCTION_ARGS)
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{
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text *str = PG_GETARG_TEXT_PP(0);
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const char *p = VARDATA_ANY(str);
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int len = VARSIZE_ANY_EXHDR(str);
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int n = PG_GETARG_INT32(1);
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int off;
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if (n < 0)
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n = -n;
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else
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n = pg_mbstrlen_with_len(p, len) - n;
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off = pg_mbcharcliplen(p, len, n);
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PG_RETURN_TEXT_P(cstring_to_text_with_len(p + off, len - off));
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}
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/*
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* Return reversed string
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*/
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Datum
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text_reverse(PG_FUNCTION_ARGS)
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{
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text *str = PG_GETARG_TEXT_PP(0);
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const char *p = VARDATA_ANY(str);
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int len = VARSIZE_ANY_EXHDR(str);
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const char *endp = p + len;
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text *result;
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char *dst;
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result = palloc(len + VARHDRSZ);
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dst = (char*) VARDATA(result) + len;
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SET_VARSIZE(result, len + VARHDRSZ);
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if (pg_database_encoding_max_length() > 1)
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{
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/* multibyte version */
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while (p < endp)
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{
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int sz;
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sz = pg_mblen(p);
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dst -= sz;
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memcpy(dst, p, sz);
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p += sz;
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}
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}
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else
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{
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/* single byte version */
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while (p < endp)
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*(--dst) = *p++;
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}
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PG_RETURN_TEXT_P(result);
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}
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@ -37,7 +37,7 @@
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* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.596 2010/08/21 10:59:17 mha Exp $
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* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.597 2010/08/24 06:30:43 itagaki Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -53,6 +53,6 @@
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*/
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/* yyyymmddN */
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#define CATALOG_VERSION_NO 201008211
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#define CATALOG_VERSION_NO 201008241
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#endif
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.580 2010/08/21 10:59:17 mha Exp $
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* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.581 2010/08/24 06:30:43 itagaki Exp $
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*
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* NOTES
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* The script catalog/genbki.pl reads this file and generates .bki
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@ -2722,6 +2722,16 @@ DESCR("I/O");
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DATA(insert OID = 1799 ( oidout PGNSP PGUID 12 1 0 0 f f f t f i 1 0 2275 "26" _null_ _null_ _null_ _null_ oidout _null_ _null_ _null_ ));
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DESCR("I/O");
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DATA(insert OID = 3058 ( concat PGNSP PGUID 12 1 0 2276 f f f f f s 1 0 25 "2276" "{2276}" "{v}" _null_ _null_ text_concat _null_ _null_ _null_ ));
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DESCR("concatenate values");
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DATA(insert OID = 3059 ( concat_ws PGNSP PGUID 12 1 0 2276 f f f f f s 2 0 25 "25 2276" "{25,2276}" "{i,v}" _null_ _null_ text_concat_ws _null_ _null_ _null_ ));
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DESCR("concatenate values with separators");
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DATA(insert OID = 3060 ( left PGNSP PGUID 12 1 0 0 f f f t f i 2 0 25 "25 23" _null_ _null_ _null_ _null_ text_left _null_ _null_ _null_ ));
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DESCR("return the first n characters");
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DATA(insert OID = 3061 ( right PGNSP PGUID 12 1 0 0 f f f t f i 2 0 25 "25 23" _null_ _null_ _null_ _null_ text_right _null_ _null_ _null_ ));
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DESCR("return the last n characters");
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DATA(insert OID = 3062 ( reverse PGNSP PGUID 12 1 0 0 f f f t f i 1 0 25 "25" _null_ _null_ _null_ _null_ text_reverse _null_ _null_ _null_ ));
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DESCR("reverse text");
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DATA(insert OID = 1810 ( bit_length PGNSP PGUID 14 1 0 0 f f f t f i 1 0 23 "17" _null_ _null_ _null_ _null_ "select pg_catalog.octet_length($1) * 8" _null_ _null_ _null_ ));
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DESCR("length in bits");
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.354 2010/08/10 21:51:00 tgl Exp $
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* $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.355 2010/08/24 06:30:44 itagaki Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -733,6 +733,12 @@ extern Datum pg_column_size(PG_FUNCTION_ARGS);
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extern Datum string_agg_transfn(PG_FUNCTION_ARGS);
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extern Datum string_agg_finalfn(PG_FUNCTION_ARGS);
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extern Datum text_concat(PG_FUNCTION_ARGS);
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extern Datum text_concat_ws(PG_FUNCTION_ARGS);
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extern Datum text_left(PG_FUNCTION_ARGS);
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extern Datum text_right(PG_FUNCTION_ARGS);
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extern Datum text_reverse(PG_FUNCTION_ARGS);
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/* version.c */
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extern Datum pgsql_version(PG_FUNCTION_ARGS);
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@ -51,3 +51,70 @@ ERROR: operator does not exist: integer || numeric
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LINE 1: select 3 || 4.0;
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^
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HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
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/*
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* string functions
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*/
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select concat('one');
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concat
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--------
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one
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(1 row)
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select concat(1,2,3,'hello',true, false, to_date('20100309','YYYYMMDD'));
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concat
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----------------------
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123hellotf03-09-2010
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(1 row)
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select concat_ws('#','one');
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concat_ws
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-----------
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one
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(1 row)
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select concat_ws('#',1,2,3,'hello',true, false, to_date('20100309','YYYYMMDD'));
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concat_ws
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----------------------------
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1#2#3#hello#t#f#03-09-2010
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(1 row)
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select concat_ws(',',10,20,null,30);
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concat_ws
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-----------
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10,20,30
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(1 row)
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select concat_ws('',10,20,null,30);
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concat_ws
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-----------
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102030
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(1 row)
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select concat_ws(NULL,10,20,null,30) is null;
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?column?
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----------
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t
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(1 row)
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select reverse('abcde');
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reverse
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---------
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edcba
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(1 row)
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select i, left('ahoj', i), right('ahoj', i) from generate_series(-5, 5) t(i) order by i;
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i | left | right
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----+------+-------
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-5 | |
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-4 | |
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-3 | a | j
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-2 | ah | oj
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-1 | aho | hoj
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0 | |
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1 | a | j
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2 | ah | oj
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3 | aho | hoj
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4 | ahoj | ahoj
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5 | ahoj | ahoj
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(11 rows)
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@ -28,3 +28,16 @@ select 'four: ' || 2+2;
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-- but not this:
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select 3 || 4.0;
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/*
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* string functions
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*/
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select concat('one');
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select concat(1,2,3,'hello',true, false, to_date('20100309','YYYYMMDD'));
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select concat_ws('#','one');
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select concat_ws('#',1,2,3,'hello',true, false, to_date('20100309','YYYYMMDD'));
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select concat_ws(',',10,20,null,30);
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select concat_ws('',10,20,null,30);
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select concat_ws(NULL,10,20,null,30) is null;
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select reverse('abcde');
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select i, left('ahoj', i), right('ahoj', i) from generate_series(-5, 5) t(i) order by i;
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