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合并两个MySQL字段并用结果更新第三个字段？

2024-05-10 00:34:05 395

以下是在MySQL中结合两个字段的语法-

alter table yourTableName add column yourColumnName dataType;
 update yourTableName set yourAddedColumnName =concat(yourColumnName1,' ',yourColumnName2);

让我们首先创建一个表-

mysql> create table DemoTable1590
   -> (
   -> FirstName varchar(20),
   -> LastName varchar(20)
   -> );

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable1590 values('Adam','Smith');
mysql> insert into DemoTable1590 values('John','Doe');
mysql> insert into DemoTable1590 values('David','Miller');

使用select语句显示表中的所有记录-

mysql> select * from DemoTable1590;

这将产生以下输出-

+-----------+----------+
| FirstName | LastName |
+-----------+----------+
| Adam      |    Smith |
| John      |      Doe |
| David     |   Miller |
+-----------+----------+
3 rows in set (0.00 sec)

以下是合并两个MySQL字段并在连接后更新第三个字段的查询-

mysql> alter table DemoTable1590 add column FullName varchar(40);
Records: 0  Duplicates: 0  Warnings: 0
mysql> update DemoTable1590 set FullName=concat(FirstName,' ',LastName);
Rows matched: 3  Changed: 3 Warnings: 0

让我们再次检查表记录-

mysql> select * from DemoTable1590;

这将产生以下输出-

+-----------+----------+--------------+
| FirstName | LastName | FullName     |
+-----------+----------+--------------+
| Adam      |    Smith | Adam Smith   |
| John      |      Doe | John Doe     |
| David     |   Miller | David Miller |
+-----------+----------+--------------+
3 rows in set (0.00 sec)

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合并两个MySQL字段并用结果更新第三个字段？

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