此功能同Oracle一样!
许多人都觉得MySQL不支持嵌套查询,其实MySQl从4.11版后已经完全支持嵌套查询了,那么下面我举些简单的嵌套查询的例子吧(源程序来自MySQL User Manual):
1. SELECT语句的子查询:
语法: (注意:AS 可省略)
例如:
SELECT sb1,sb2,sb3 FROM (SELECT s1 AS sb1, s2 AS sb2, s3*2 AS sb3 FROM t1) AS sb WHERE sb1 > 1; |
CODE: | ||
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.2.行的子查询(Row Subquery):
CODE: | ||
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3.使用Exist和Not Exist参数
这里的Exist和Not Exist用途及用法和在其他没有什么大的区别,我就简单举几个范例好了:
CODE: | |
SELECT DISTINCT store_type FROM Stores WHERE EXISTS (SELECT * FROM Cities_Stores WHERE Cities_Stores.store_type = Stores.store_type); |
CODE:
SELECT DISTINCT store_type FROM Stores
WHERE NOT EXISTS (SELECT * FROM Cities_Stores
WHERE Cities_Stores.store_type = Stores.store_type);
参考博客:https://blog.csdn.net/fantaxy025025/article/details/83848674