queryWrapper.eq

queryWrapper.eq是MyBatis中的一个方法，用于设置查询条件中的等于关系。在这段代码中，queryWrapper.eq被用来设置三个查询条件：driver_id等于driverCarBindingRelationship.getDriverId()、car_id等于driverCarBindingRelationship.getCarId()、bind_state等于DriverCarConstants.DRIVER_CAR_BIND。这样设置了查询条件后，代码会执行selectCount方法查询数据库中满足这三个条件的记录数量，并将结果存储在integer变量中。

如果integer大于0，说明已经存在满足这三个条件的记录，即司机和车辆关系已经绑定过，所以返回一个失败的响应结果，表示不允许再次绑定。

相关问题

QueryWrapper.eq

QueryWrapper.eq is a method in the MyBatis Plus library for building SQL queries. It is used to add a condition to the query that checks if a column in the database table is equal to a specific value.

For example, consider the following code snippet:

QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.eq("username", "john_doe");
List<User> users = userMapper.selectList(wrapper);

In this example, the QueryWrapper object is created and the "eq" method is used to add a condition to the query. The condition checks if the "username" column in the "User" table is equal to "john_doe". The "selectList" method is then called on the userMapper object to execute the query and retrieve a list of users who match the condition.

querywrapper.eq

queryWrapper.eq方法是QueryWrapper类中的一个方法，用于构建等值条件查询。它可以根据指定的列名和值来查询符合条件的数据。例如，在给定的QueryWrapper对象queryWrapper中，可以使用eq方法来查询card_no字段值为1001的数据，即queryWrapper.eq("card_no",1001)。\[2\]这个方法还可以与其他条件查询方法一起使用，比如le方法用于查询小于等于某个值的数据，ge方法用于查询大于等于某个值的数据，like方法用于模糊查询等等。\[3\]
#### 引用[.reference_title]
- *1* [QueryWrapper中eq的用法案例](https://blog.csdn.net/weixin_59479961/article/details/128019960)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^insert_down1,239^v3^insert_chatgpt"}} ] [.reference_item]
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