mysql select from where in

`SELECT` 语句用于从数据库中检索数据。`WHERE` 子句用于指定检索条件。`IN` 运算符用于指定范围，它允许您指定多个值作为搜索条件。

语法如下：

SELECT column_name(s) FROM table_name WHERE column_name IN (value1, value2, ...);

例如，从 `employees` 表中选择工资为 20000 或 25000 的员工：

SELECT * FROM employees WHERE salary IN (20000, 25000);

相关问题

mysql select from where notin

可以使用 NOT IN 子句来在 MySQL 中筛选不在指定列表中的行。以下是一个例子：

SELECT * FROM mytable WHERE mycolumn NOT IN ('value1', 'value2', 'value3');

在这个例子中，`mytable` 是表的名称，`mycolumn` 是需要筛选的列的名称，`value1`、`value2` 和 `value3` 是不希望出现在结果中的值。

你也可以在 `NOT IN` 子句中使用子查询来获取需要排除的值，例如：

SELECT * FROM mytable WHERE mycolumn NOT IN (SELECT mycolumn FROM myothertable);

在这个例子中，`myothertable` 是另一个表的名称，它包含了需要排除的值。

mysql select from where when

The "SELECT FROM WHERE" clause is used in MySQL to retrieve data from a table based on certain conditions.

Here is an example of how to use the SELECT FROM WHERE clause in MySQL:

SELECT column1, column2, ...
FROM table_name
WHERE condition;

- "column1, column2, ..." are the columns that you want to retrieve data from.
- "table_name" is the name of the table that you want to retrieve data from.
- "condition" is the condition that you want to apply to retrieve data.

For example, to retrieve all the rows from the "users" table where the age is greater than or equal to 18, you can use the following query:

SELECT * FROM users WHERE age >= 18;

This will retrieve all the columns and rows from the "users" table where the age is greater than or equal to 18.