如何在PL / PGSQL中为JSON实现自定义相等运算符

问题描述

尝试对通过集合运算符连接的子查询进行超级查询时遇到问题：

SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='air') = ANY(tags)
UNION
(SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='horse') != ANY(tags)
INTERSECT
SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='train') = ANY(tags))
UNION
SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='sea') = ANY(tags)
UNION
SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='foot') != ANY(tags)
UNION
(SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='anchor') = ANY(tags)
UNION
(SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='field') != ANY(tags)
UNION
SELECT * FROM artworks WHERE (SELECT id FROM art_tags WHERE name='gray') = ANY(tags)))

处理器给我一个问题，原因是行中有json元素。 “无法识别json类型的相等运算符”。因此，我尝试自己实施。代码如下（不包括功能）：

DROP OPERATOR = (json,json);
CREATE OPERATOR = (
  LEFTARG = JSON,RIGHTARG = JSON,PROCEDURE = COMPARE_JSON,COMMUTATOR = =,NEGATOR = !=,HASHES,MERGES
);

当执行相同的超级查询时，我仍收到相同的反馈“无法为json类型标识相等运算符”。您如何实现特定类型的运算符，以使plsql引擎能够识别出该运算符？

解决方法

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json plpgsql