单个查询中的MySQL UNION SELECT和IN子句
让我们首先创建一个表-
create table DemoTable1 -> ( -> StudentId int, -> StudentName varchar(20) -> );
使用插入命令在表中插入一些记录-
insert into DemoTable1 values(210,'Adam');
使用select语句显示表中的所有记录-
select * from DemoTable1;
这将产生以下输出-
+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | 210 | Adam | +-----------+-------------+ 1 row in set (0.00 sec)
这是创建第二个表的查询-
create table DemoTable2 -> ( -> StudentId int, -> StudentName varchar(20) -> );
使用插入命令在表中插入一些记录-
insert into DemoTable2 values(100,'Chris');
使用select语句显示表中的所有记录-
select * from DemoTable2;
这将产生以下输出-
+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | 100 | Chris | +-----------+-------------+ 1 row in set (0.00 sec)
这是对MySQLUNIONSELECT和IN子句的查询-
select StudentName from -> ( -> select StudentId,StudentName from DemoTable1 -> UNION -> select StudentId,StudentName from DemoTable2 -> ) tbl -> where StudentId IN(210,100);
这将产生以下输出-
+-------------+ | StudentName | +-------------+ | Adam | | Chris | +-------------+ 2 rows in set (0.00 sec)