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Commit01f7808

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Add a cardinality function for arrays.
Unlike our other array functions, this considers the total number ofelements across all dimensions, and returns 0 rather than NULL when thearray has no elements. But it seems that both of those behaviors arealmost universally disliked, so hopefully that's OK.Marko Tiikkaja, reviewed by Dean Rasheed and Pavel Stehule
1 parent033b234 commit01f7808

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8 files changed

+93
-1
lines changed

8 files changed

+93
-1
lines changed

‎doc/src/sgml/array.sgml‎

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@@ -337,6 +337,19 @@ SELECT array_length(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>cardinality</function> returns the total number of elements in an
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array across all dimensions. It is effectively the number of rows a call to
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<function>unnest</function> would yield:
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<programlisting>
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SELECT cardinality(schedule) FROM sal_emp WHERE name = 'Carol';
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cardinality
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-------------
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4
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(1 row)
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</programlisting>
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</para>
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</sect2>

‎doc/src/sgml/func.sgml‎

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@@ -11008,6 +11008,9 @@ SELECT NULLIF(value, '(none)') ...
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<indexterm>
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<primary>array_upper</primary>
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</indexterm>
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<indexterm>
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<primary>cardinality</primary>
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</indexterm>
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<indexterm>
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<primary>string_to_array</primary>
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</indexterm>
@@ -11164,6 +11167,17 @@ SELECT NULLIF(value, '(none)') ...
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<entry><literal>array_upper(ARRAY[1,8,3,7], 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 total number of elements in the array, or 0 if the array is empty</entry>
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<entry><literal>cardinality(ARRAY[[1,2],[3,4]])</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>

‎src/backend/utils/adt/arrayfuncs.c‎

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@@ -1739,6 +1739,18 @@ array_length(PG_FUNCTION_ARGS)
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PG_RETURN_INT32(result);
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}
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/*
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* array_cardinality:
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*returns the total number of elements in an array
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*/
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Datum
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array_cardinality(PG_FUNCTION_ARGS)
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{
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ArrayType*v=PG_GETARG_ARRAYTYPE_P(0);
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PG_RETURN_INT32(ArrayGetNItems(ARR_NDIM(v),ARR_DIMS(v)));
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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

‎src/include/catalog/catversion.h‎

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@@ -53,6 +53,6 @@
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*/
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/*yyyymmddN */
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#defineCATALOG_VERSION_NO201312231
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#defineCATALOG_VERSION_NO201401211
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#endif

‎src/include/catalog/pg_proc.h‎

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@@ -840,6 +840,8 @@ DATA(insert OID = 2092 ( array_upper PGNSP PGUID 12 1 0 0 0 f f f f t f i 2
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DESCR("array upper dimension");
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DATA(insertOID=2176 (array_lengthPGNSPPGUID121000fffftfi2023"2277 23"_null__null__null__null_array_length_null__null__null_ ));
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DESCR("array length");
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DATA(insertOID=3179 (cardinalityPGNSPPGUID121000fffftfi1023"2277"_null__null__null__null_array_cardinality_null__null__null_ ));
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DESCR("array cardinality");
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DATA(insertOID=378 (array_appendPGNSPPGUID121000ffffffi202277"2277 2283"_null__null__null__null_array_push_null__null__null_ ));
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DESCR("append element onto end of array");
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DATA(insertOID=379 (array_prependPGNSPPGUID121000ffffffi202277"2283 2277"_null__null__null__null_array_push_null__null__null_ ));

‎src/include/utils/array.h‎

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@@ -204,6 +204,7 @@ extern Datum array_dims(PG_FUNCTION_ARGS);
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externDatumarray_lower(PG_FUNCTION_ARGS);
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externDatumarray_upper(PG_FUNCTION_ARGS);
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externDatumarray_length(PG_FUNCTION_ARGS);
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externDatumarray_cardinality(PG_FUNCTION_ARGS);
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externDatumarray_larger(PG_FUNCTION_ARGS);
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externDatumarray_smaller(PG_FUNCTION_ARGS);
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externDatumgenerate_subscripts(PG_FUNCTION_ARGS);

‎src/test/regress/expected/arrays.out‎

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@@ -1455,6 +1455,48 @@ select array_length(array[[1,2,3], [4,5,6]], 3);
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(1 row)
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select cardinality(NULL::int[]);
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cardinality
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-------------
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(1 row)
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select cardinality('{}'::int[]);
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cardinality
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-------------
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0
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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('[2:4]={5,6,7}'::int[]);
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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('{{1,2}}'::int[]);
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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 cardinality('{{1,2},{3,4},{5,6}}'::int[]);
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cardinality
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-------------
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6
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(1 row)
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select cardinality('{{{1}},{{2,3},{3,4}}}'::int[]);
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cardinality
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-------------
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8
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(1 row)
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select array_agg(unique1) from (select unique1 from tenk1 where unique1 < 15 order by unique1) ss;
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array_agg
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--------------------------------------

‎src/test/regress/sql/arrays.sql‎

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@@ -419,6 +419,14 @@ 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(NULL::int[]);
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select cardinality('{}'::int[]);
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select cardinality(array[1,2,3]);
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select cardinality('[2:4]={5,6,7}'::int[]);
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select cardinality('{{1,2}}'::int[]);
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select cardinality('{{1,2},{3,4},{5,6}}'::int[]);
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select cardinality('{{{1}},{{2,3},{3,4}}}'::int[]);
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select array_agg(unique1)from (select unique1from tenk1where unique1<15order by unique1) ss;
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select array_agg(ten)from (select tenfrom tenk1where unique1<15order by unique1) ss;
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select array_agg(nullif(ten,4))from (select tenfrom tenk1where unique1<15order by unique1) ss;

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