mysql 交集 差集 并集

交集

SELECT
	a.*,
	b.*
FROM
	a
JOIN b ON
	a.id = b.id;

差集

SELECT * FROM table_a ta
EXCEPT
SELECT * FROM table_b tb ;
-------------------------------------------
SELECT ta.* FROM table_a ta
WHERE ta.a NOT in  (SELECT ta.a FROM table_a ta JOIN table_b tb ON ta.a=tb.a )

并集

SELECT * FROM table_a ta
union #或者union all
SELECT * FROM table_b tb ;

区别:
union 去重
union all 不去重