MySQL SELECT INTO 相当于什么？

SELECT INTO 相当于 CREATE TABLE AS SELECT 语句。其语法如下 –

CREATE TABLE yourNewTableName AS SELECT *FROM yourTableName;

为了理解上述概念，让我们创建一张表。创建表的查询语句如下 –

mysql> create table selectIntoEquivalentDemo
  -> (
  -> ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
  -> ClientName varchar(20),
  -> ClientAge int
  -> );
Query OK, 0 rows affected (0.71 sec)

使用 INSERT 语句向表中插入一些记录。查询语句如下 –

mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('Larry',34);
Query OK, 1 row affected (0.13 sec)
mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('Maxwell',44);
Query OK, 1 row affected (0.06 sec)
mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('Bob',38);
Query OK, 1 row affected (0.07 sec)
mysql> insert into selectIntoEquivalentDemo(ClientName,ClientAge) values('David',39);
Query OK, 1 row affected (0.09 sec)

使用 SELECT 语句显示表中的所有记录。查询语句如下 –

mysql> select *from selectIntoEquivalentDemo

输出结果如下 –

+----------+------------+-----------+
| ClientId | ClientName | ClientAge |
+----------+------------+-----------+
| 1        | Larry      | 34        |
| 2        | Maxwell    | 44        |
| 3        | Bob        | 38        |
| 4        | David      | 39        |
+----------+------------+-----------+
4 rows in set (0.00 sec)

下面是 MySQL 中 SELECT INTO 相当于的查询 –

mysql> create table Client_information AS select *from selectIntoEquivalentDemo;
Query OK, 4 rows affected (0.57 sec)
Records: 4 Duplicates: 0 Warnings: 0

现在，让我们从新表中检查表记录。查询语句如下 –

mysql> select *from Client_information;

输出结果如下 –

+----------+------------+-----------+
| 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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