SELECT * FROM A WHERE EXISTS (SELECT 1 FROM B WHERE A.id = B.job_id AND B.site_id = '2')
SELECT * FROM A WHERE a.id IN (SELECT B.job_id FROM B WHERE B.site_id = '2')
请问,在上述条件下,那种SQL速度更快?请大侠指教
...全文
44回复打赏收藏
SQL基础优化
现在做一个网站!有这样一个问题需要大家帮忙: 现在有两个表 A job表 B job与地区关系表 B表的数据量是A表的2~3倍,为了提取A表数据,现有如下SQL: SELECT * FROM A WHERE EXISTS (SELECT 1 FROM B WHERE A.id = B.job_id AND B.site_id = '2') SELECT * FROM A WHERE a.id IN (SELECT B.job_id FROM B WHERE B.site_id = '2') 请问