什么是MySQL SELECT INTO等效项?
SELECT INTO等效项是CREATE TABLE AS SELECT语句。语法如下-
CREATE TABLE yourNewTableName AS SELECT *FROM yourTableName;
为了理解上述概念,让我们创建一个表。创建表的查询如下-
mysql> create table selectIntoEquivalentDemo-> (
-> ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
-> ClientName varchar(20),
-> ClientAge int
-> );
使用insert命令在表中插入一些记录。查询如下-
mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('Larry',34);mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('Maxwell',44);
mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('Bob',38);
mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('David',39);
使用select语句显示表中的所有记录。查询如下-
mysql> select *from selectIntoEquivalentDemo
这是输出-
+----------+------------+-----------+| ClientId | ClientName | ClientAge |
+----------+------------+-----------+
| 1 | Larry | 34 |
| 2 | Maxwell | 44 |
| 3 | Bob | 38 |
| 4 | David | 39 |
+----------+------------+-----------+
4 rows in set (0.00 sec)
以下是MySQL中的SELECT INTO等效查询-
mysql> create table Client_information AS select *from selectIntoEquivalentDemo;Records: 4 Duplicates: 0 Warnings: 0
现在,让我们检查新表中的表记录。查询如下-
mysql> select *from Client_information;
这是输出-
+----------+------------+-----------+| ClientId | ClientName | ClientAge |
+----------+------------+-----------+
| 1 | Larry | 34 |
| 2 | Maxwell | 44 |
| 3 | Bob | 38 |
| 4 | David | 39 |
+----------+------------+-----------+
4 rows in set (0.00 sec)
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