PostgreSQL

Question

我正在尝试编写一个函数，如果我将一个变量传递给该函数，那么根据该变量的值，应该执行不同的查询。

CREATE OR REPLACE FUNCTION SW_Versions(VersionType varchar)
RETURNS TABLE(array_sw_version varchar) AS $$
BEGIN

IF VersionType = 'All' THEN

    EXECUTE 'select ''1'' as array1_sw_version UNION ALL
        select ''2'' as array1_sw_version';

ELSIF VersionType = 'Major' THEN

    EXECUTE 'select ''A'' as array2_sw_version UNION ALL
        select ''B'' as array2_sw_version';

ELSE
    EXECUTE 'select ''X'' as array3_sw_version UNION ALL
        select ''Y'' as array3_sw_version';
END IF;

END;
$$ LANGUAGE plpgsql STRICT;

SELECT SW_Versions('Major')

上面的查询没有产生正确的结果，应该是 2。谁能帮我找出我做错了什么？

Answer 1

你不需要EXECUTE。请改用 RETURN QUERY。添加了转换 (::varchar) 以提供列类型兼容性。

CREATE OR REPLACE FUNCTION SW_Versions(VersionType varchar)
RETURNS TABLE(array_sw_version varchar) AS $$
BEGIN

IF VersionType = 'All' THEN

    RETURN QUERY select '1'::varchar as array1_sw_version UNION ALL
        select '2'::varchar as array1_sw_version;

ELSIF VersionType = 'Major' THEN

    RETURN QUERY select 'A'::varchar as array2_sw_version UNION ALL
        select 'B'::varchar as array2_sw_version;

ELSE
    RETURN QUERY select 'X'::varchar as array3_sw_version UNION ALL
        select 'Y'::varchar as array3_sw_version;
END IF;

END;
$$ LANGUAGE plpgsql STRICT;

SELECT SW_Versions('Major')

PostgreSQL - 如何在函数中动态执行查询 return table

PostgreSQL - How to dynamically execute a query in a function and return table

sql

plpgsql