postgresql 转换数组类型
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Conversion array types
提问by Oto Shavadze
I have in table column, which type is CHARACTER VARYING[](that is array)
我在表列中，哪种类型是CHARACTER VARYING[]（即数组）
I need concatenate existed rows whith other array
我需要连接其他数组的现有行
This is my code:
这是我的代码：
UPDATE my_table SET
col = array_cat(col, ARRAY['5','6','7'])
returned error: function array_cat(character varying[], text[]) does not exist
返回错误： function array_cat(character varying[], text[]) does not exist
Reason error is that array types not matches right?
原因错误是数组类型不匹配吗？
Question: how to convert this array ARRAY['5','6','7']as CHARACTER VARYING[]type ?
问题：如何将此数组转换ARRAY['5','6','7']为CHARACTER VARYING[]类型？
回答by Craig Ringer
Cast to varchar[]:
投射到varchar[]：
> SELECT ARRAY['5','6','7']::varchar[], pg_typeof( ARRAY['5','6','7']::varchar[] );
SELECT ARRAY['5','6','7']::varchar[], pg_typeof( ARRAY['5','6','7']::varchar[] );
array | pg_typeof
---------+---------------------
{5,6,7} | character varying[]
You can use the PostgreSQL specific ::varchar[]or the standard CAST(colname AS varchar[])... though as arrays are not consistent across database implementations there won't be much advantage to using the standard syntax.
您可以使用特定于 PostgreSQL 的::varchar[]或标准的CAST(colname AS varchar[])......尽管由于数组在数据库实现中不一致，使用标准语法不会有太大优势。
