我有一个嵌套查询,并尝试查看查询中是否有任何全表扫描。delete from ACCESS where ACCESS.MESSAGEID in (select ID from MESSAGE where MESSAGE.CID = 'xzy67sd’)\G key_len: 8 rows: 1
Extra: Using where
我正在尝试执行以下查询。share set holder = 22 where SHARE_ID IN (select SHARE_ID from SHARE WHERE holder=1 LIMIT 10)#1235 - This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'
., k1 INTEGER, k2 INTEGER)SELECT * FROM foo WHERE (k1 BETWEEN @a AND @b) AND (k2 BETWEEN一篇MySQL性能博客文章可能指出,它不应该这样做,因为一旦使用了间隔范围,它就只扫描其余的:我想在k1上分区的地方使用分区。文档说优化器会考虑到这一点。如果我创建了许多分区,并且数据相当分散,那么如果引