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从MySQL表的列中选择并仅显示一些行

2024-04-22 04:33:03 397

让我们首先创建一个表-

mysql> create table DemoTable625 (
   StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,StudentFirstName varchar(100),StudentScore int
);

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable625(StudentFirstName,StudentScore) values('John',98);
mysql> insert into DemoTable625(StudentFirstName,StudentScore) values('Chris',39);
mysql> insert into DemoTable625(StudentFirstName,StudentScore) values('Bob',41);
mysql> insert into DemoTable625(StudentFirstName,StudentScore) values('David',40);
mysql> insert into DemoTable625(StudentFirstName,StudentScore) values('Robert',52);

使用select语句显示表中的所有记录-

mysql> select *from DemoTable625;

这将产生以下输出-

+-----------+------------------+--------------+
| StudentId | StudentFirstName | StudentScore |
+-----------+------------------+--------------+
|         1 | John             |           98 |
|         2 | Chris            |           39 |
|         3 | Bob              |           41 |
|         4 | David            |           40 |
|         5 | Robert           | 52 |
+-----------+------------------+--------------+
5 rows in set (0.00 sec)

这是用于选择和仅显示一些行的查询-

mysql> select *from DemoTable625 where StudentFirstName NOT IN(
   select StudentFirstName from DemoTable625
   where StudentScore < 50
);

这将产生以下输出-

+-----------+------------------+--------------+
| StudentId | StudentFirstName | StudentScore |
+-----------+------------------+--------------+
|         1 | John             |           98 |
|         5 | Robert           |           52 |
+-----------+------------------+--------------+
2 rows in set (0.00 sec)

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从MySQL表的列中选择并仅显示一些行

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