array_length() function, and for SQL compatibility also cardinality()
function as a special case. This version still has the suspicious behavior of returning null for an empty array (rather than zero), but this may need a wholesale revision of empty array behavior, currently under discussion. Jim Nasby, Robert Haas, Peter Eisentraut
This commit is contained in:
Peter Eisentraut
parent
4c22564471
commit
f98f6ee064
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.67 2008/10/29 11:24:52 petere Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.68 2008/11/12 13:09:27 petere Exp $ -->
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<sect1 id="arrays">
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<title>Arrays</title>
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@ -324,6 +324,18 @@ SELECT array_upper(schedule, 1) FROM sal_emp WHERE name = 'Carol';
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-------------
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2
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(1 row)
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</programlisting>
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<function>array_length</function> will return the length of a specified
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array dimension:
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<programlisting>
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SELECT array_length(schedule, 1) FROM sal_emp WHERE name = 'Carol';
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array_length
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--------------
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2
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(1 row)
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</programlisting>
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</para>
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</sect2>
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.456 2008/11/07 22:54:41 tgl Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.457 2008/11/12 13:09:27 petere Exp $ -->
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<chapter id="functions">
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<title>Functions and Operators</title>
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@ -9408,6 +9408,17 @@ SELECT NULLIF(value, '(none)') ...
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<entry><literal>array_fill(7, ARRAY[3], ARRAY[2])</literal></entry>
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<entry><literal>[2:4]={7,7,7}</literal></entry>
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</row>
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<row>
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<entry>
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<literal>
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<function>array_length</function>(<type>anyarray</type>, <type>int</type>)
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</literal>
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</entry>
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<entry><type>int</type></entry>
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<entry>returns the length of the requested array dimension</entry>
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<entry><literal>array_length(array[1,2,3], 1)</literal></entry>
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<entry><literal>3</literal></entry>
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</row>
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<row>
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<entry>
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<literal>
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@ -9452,6 +9463,19 @@ SELECT NULLIF(value, '(none)') ...
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<entry><literal>array_upper(ARRAY[1,2,3,4], 1)</literal></entry>
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<entry><literal>4</literal></entry>
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</row>
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<row>
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<entry>
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<literal>
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<function>cardinality</function>(<type>anyarray</type>)
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</literal>
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</entry>
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<entry><type>int</type></entry>
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<entry>returns the length of the first dimension of the array
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(special case of <function>array_length</function> for SQL
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compatibility)</entry>
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<entry><literal>cardinality(array[1,2,3])</literal></entry>
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<entry><literal>3</literal></entry>
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</row>
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<row>
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<entry>
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<literal>
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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/arrayfuncs.c,v 1.148 2008/11/04 14:49:11 petere Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.149 2008/11/12 13:09:27 petere Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -1640,6 +1640,34 @@ array_upper(PG_FUNCTION_ARGS)
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PG_RETURN_INT32(result);
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}
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/*
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* array_length :
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* returns the length, of the dimension requested, for
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* the array pointed to by "v", as an int4
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*/
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Datum
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array_length(PG_FUNCTION_ARGS)
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{
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ArrayType *v = PG_GETARG_ARRAYTYPE_P(0);
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int reqdim = PG_GETARG_INT32(1);
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int *dimv;
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int result;
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/* Sanity check: does it look like an array at all? */
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if (ARR_NDIM(v) <= 0 || ARR_NDIM(v) > MAXDIM)
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PG_RETURN_NULL();
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/* Sanity check: was the requested dim valid */
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if (reqdim <= 0 || reqdim > ARR_NDIM(v))
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PG_RETURN_NULL();
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dimv = ARR_DIMS(v);
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result = dimv[reqdim - 1];
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PG_RETURN_INT32(result);
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}
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/*
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* array_ref :
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* This routine takes an array pointer and a subscript array and returns
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@ -37,7 +37,7 @@
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* Portions Copyright (c) 1996-2008, 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 1.503 2008/11/09 21:24:33 tgl Exp $
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* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.504 2008/11/12 13:09:27 petere 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 200811091
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#define CATALOG_VERSION_NO 200811121
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#endif
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2008, 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 1.524 2008/11/04 14:49:11 petere Exp $
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* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.525 2008/11/12 13:09:28 petere Exp $
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*
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* NOTES
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* The script catalog/genbki.sh reads this file and generates .bki
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@ -996,6 +996,10 @@ DATA(insert OID = 2091 ( array_lower PGNSP PGUID 12 1 0 0 f f t f i 2 23 "22
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DESCR("array lower dimension");
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DATA(insert OID = 2092 ( array_upper PGNSP PGUID 12 1 0 0 f f t f i 2 23 "2277 23" _null_ _null_ _null_ array_upper _null_ _null_ _null_ ));
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DESCR("array upper dimension");
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DATA(insert OID = 2176 ( array_length PGNSP PGUID 12 1 0 0 f f t f i 2 23 "2277 23" _null_ _null_ _null_ array_length _null_ _null_ _null_ ));
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DESCR("array length");
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DATA(insert OID = 2179 ( cardinality PGNSP PGUID 14 1 0 0 f f t f i 1 23 "2277" _null_ _null_ _null_ "select array_length($1, 1)" _null_ _null_ _null_ ));
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DESCR("array length");
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DATA(insert OID = 378 ( array_append PGNSP PGUID 12 1 0 0 f f f f i 2 2277 "2277 2283" _null_ _null_ _null_ array_push _null_ _null_ _null_ ));
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DESCR("append element onto end of array");
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DATA(insert OID = 379 ( array_prepend PGNSP PGUID 12 1 0 0 f f f f i 2 2277 "2283 2277" _null_ _null_ _null_ array_push _null_ _null_ _null_ ));
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@ -49,7 +49,7 @@
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* Portions Copyright (c) 1996-2008, 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/array.h,v 1.69 2008/11/04 14:49:12 petere Exp $
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* $PostgreSQL: pgsql/src/include/utils/array.h,v 1.70 2008/11/12 13:09:28 petere Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -199,6 +199,7 @@ extern Datum array_ndims(PG_FUNCTION_ARGS);
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extern Datum array_dims(PG_FUNCTION_ARGS);
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extern Datum array_lower(PG_FUNCTION_ARGS);
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extern Datum array_upper(PG_FUNCTION_ARGS);
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extern Datum array_length(PG_FUNCTION_ARGS);
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extern Datum array_larger(PG_FUNCTION_ARGS);
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extern Datum array_smaller(PG_FUNCTION_ARGS);
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extern Datum generate_subscripts(PG_FUNCTION_ARGS);
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1|2|3
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(1 row)
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select array_length(array[1,2,3], 1);
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array_length
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--------------
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3
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(1 row)
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select array_length(array[[1,2,3], [4,5,6]], 0);
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array_length
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--------------
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(1 row)
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select array_length(array[[1,2,3], [4,5,6]], 1);
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array_length
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--------------
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2
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(1 row)
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select array_length(array[[1,2,3], [4,5,6]], 2);
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array_length
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--------------
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3
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(1 row)
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select array_length(array[[1,2,3], [4,5,6]], 3);
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array_length
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--------------
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(1 row)
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select cardinality(array[1,2,3]);
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cardinality
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-------------
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3
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(1 row)
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select cardinality(array[[1,2,3], [4,5,6]]);
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cardinality
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-------------
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2
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(1 row)
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select c, cardinality(c), d, cardinality(d) from arrtest;
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c | cardinality | d | cardinality
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-------------------+-------------+---------------+-------------
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{} | | {} |
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{foobar,new_word} | 2 | {{elt1,elt2}} | 1
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{foo,new_word} | 2 | {bar,foo} | 2
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(3 rows)
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@ -386,3 +386,12 @@ select string_to_array('1|2|3', NULL);
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select string_to_array(NULL, '|');
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select array_to_string(string_to_array('1|2|3', '|'), '|');
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select array_length(array[1,2,3], 1);
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select array_length(array[[1,2,3], [4,5,6]], 0);
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select array_length(array[[1,2,3], [4,5,6]], 1);
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select array_length(array[[1,2,3], [4,5,6]], 2);
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select array_length(array[[1,2,3], [4,5,6]], 3);
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select cardinality(array[1,2,3]);
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select cardinality(array[[1,2,3], [4,5,6]]);
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select c, cardinality(c), d, cardinality(d) from arrtest;
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