当尝试将JSONB_ARRAY_ELEMENTS调用的结果分配给VARCHAR 数组(供以后在SELECT ... WHERE IN (UNNEST(...))
语句中使用)时,以下存储函数:
CREATE OR REPLACE FUNCTION test1(
IN in_sids jsonb,
OUT out_uid integer)
RETURNS integer AS
$func$
DECLARE
sids varchar[];
uids integer[];
BEGIN
sids := (SELECT x->>'sid' FROM JSONB_ARRAY_ELEMENTS(in_sids) x);
-- uids := (SELECT uid FROM social WHERE sid IN (UNNEST(sids)));
RAISE NOTICE 'sids = %', sids;
RAISE NOTICE 'uids = %', uids;
SELECT 1;
END
$func$ LANGUAGE plpgsql;
不幸的是打印错误:
# select test1('[{"sid":"aaa"},{"sid":"bbb"}]'::jsonb);
ERROR: more than one row returned by a subquery used as an expression
CONTEXT: SQL statement "SELECT (SELECT x->>'sid' FROM JSONB_ARRAY_ELEMENTS(in_sids) x)"
PL/pgSQL function test1(jsonb) line 6 at assignment
所以我试图通过使用ARRAY_AGG来修复分配-
sids := SELECT ARRAY_AGG(SELECT x->>'sid' FROM JSONB_ARRAY_ELEMENTS(in_sids) x);
但得到语法错误:
ERROR: syntax error at or near "SELECT"
LINE 10: sids := SELECT ARRAY_AGG(SELECT x->>'sid' FROM JSONB...
^
请问如何将JSONB_ARRAY_ELEMENTS
结果存储到数组中?
更新:
我听从了尼克的建议(谢谢),但现在卡在下一步:
CREATE OR REPLACE FUNCTION test1(
IN in_sids jsonb,
OUT out_uid integer)
RETURNS integer AS
$func$
DECLARE
sids varchar[];
uids integer[];
BEGIN
sids := (SELECT ARRAY_AGG(x->>'sid') FROM JSONB_ARRAY_ELEMENTS(in_sids) x);
uids := (SELECT uid FROM social WHERE sid IN (UNNEST(sids)));
SELECT 1;
END
$func$ LANGUAGE plpgsql;
尝试在SELECT ... WHERE IN ...
语句中使用数组时:
# select test1('[{"sid":"aaa"},{"sid":"bbb"}]'::jsonb);
ERROR: argument of IN must not return a set
LINE 1: SELECT (SELECT uid FROM social WHERE sid IN (UNNEST(si...
^
QUERY: SELECT (SELECT uid FROM social WHERE sid IN (UNNEST(sids)))
CONTEXT: PL/pgSQL function test1(jsonb) line 7 at assignment