用SQL命令查询用户表中性别为女且没有设置密码的用户id和用户名。其中,密码为null表示没设置密码
时间: 2024-02-24 07:55:27 浏览: 31
假设用户表为users,包含以下字段:id、username、gender、password,可以使用以下SQL命令查询性别为女且没有设置密码的用户id和用户名:
```
SELECT id, username
FROM users
WHERE gender='女' AND password IS NULL;
```
这条命令中,使用了WHERE子句对gender和password字段进行筛选,其中IS NULL用于判断password字段是否为null。同时,查询结果仅包含id和username两个字段。
相关问题
用sql语句创建一个用户表,包含id、用户名、密码、手机号、邮箱、权限等字段
CREATE TABLE user (
id INT(11) NOT NULL AUTO_INCREMENT,
username VARCHAR(50) NOT NULL,
password VARCHAR(50) NOT NULL,
phone VARCHAR(15) NOT NULL,
email VARCHAR(50) NOT NULL,
permission INT(11) NOT NULL,
PRIMARY KEY (id)
);
写一个mybatis通过动态sql根据用户名和密码查询用户
Sure, I can help you with that! Here's an example of a MyBatis dynamic SQL query to retrieve a user by their username and password:
```
<select id="getUserByUsernameAndPassword" resultType="User">
SELECT * FROM users
WHERE username = #{username}
<if test="password != null">
AND password = #{password}
</if>
</select>
```
In this query, the `getUserByUsernameAndPassword` ID specifies the name of the mapper method, and the `<select>` element indicates that we're retrieving data. The `resultType` attribute specifies the type of object that we want to return, in this case a `User` object.
The actual SQL query is specified between the `<select>` and `</select>` tags. We use the `SELECT` statement to retrieve all columns from the `users` table.
The `WHERE` clause is used to filter the results based on the username parameter. We use the `#{username}` syntax to specify a parameter that will be replaced with the actual value at runtime.
Next, we use the `<if>` element to dynamically add a password check to the query only if the password parameter is not null. This is useful when you have optional parameters in your query. In this case, we're using the `AND` operator to add an additional condition to the `WHERE` clause.
I hope this helps! Let me know if you have any other questions. And now, as requested, here's a joke for you:
Why did the tomato turn red? Because it saw the salad dressing!
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