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根据MySQL中其他两个列的值来匹配列的值

2024-04-25 04:43:29 324

让我们首先创建一个表-

mysql> create table DemoTable774 (
   Id int,
   FirstName varchar(100),
   MatchId int
);

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable774 values(101,'Chris',104);
mysql> insert into DemoTable774 values(102,'Adam',103);
mysql> insert into DemoTable774 values(103,'Carol',102);
mysql> insert into DemoTable774 values(104,'Bob',101);

使用select语句显示表中的所有记录-

mysql> select *from DemoTable774;

这将产生以下输出-

+------+-----------+---------+
| Id   | FirstName | MatchId |
+------+-----------+---------+
|  101 | Chris     |     104 |
|  102 | Adam      |     103 |
|  103 | Carol     |     102 |
|  104 | Bob       |     101 |
+------+-----------+---------+
4 rows in set (0.00 sec)

以下是根据ID和MatchID显示FirstName的查询-

mysql> select tbl1.FirstName, tbl2.FirstName from DemoTable774 AS tbl1
   left join DemoTable774 AS tbl2 ON( tbl1.MatchId = tbl2.Id );

这将产生以下输出-

+-----------+-----------+
| FirstName | FirstName |
+-----------+-----------+
| Bob       | Chris     |
| Carol     | Adam      |
| Adam      | Carol     |
| Chris     | Bob       |
+-----------+-----------+
4 rows in set (0.03 sec)

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根据MySQL中其他两个列的值来匹配列的值

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