Use mybatisPlus queryWrapper for left join and in-join

MybatisPlus queryWrapper does left join and in-link

Generate Java code using mybatisplus querywapper in service layer

SELECT
bs_user.id,
bs_user.mobile,
bs_user.username,
bs_user.password,
bs_user.enable_state,
ss_user_social_security.user_id,
ss_user_social_security.enterprises_pay_social_security_this_month,
ss_user_social_security.enterprises_pay_the_provident_fund_this_month,
ss_user_social_security.participating_in_the_city_id,
ss_user_social_security.social_security_type,
ss_user_social_security.household_registration_type,
ss_user_social_security.social_security_base,
ss_user_social_security.industrial_injury_ratio
FROM
bs_user
LEFT JOIN
ss_user_social_security
ON
bs_user.id = ss_user_social_security.user_id
INNER JOIN
ss_company_settings
ON
bs_user.company_id = ss_company_settings.company_id
WHERE
ss_company_settings.company_id = 1 The table structure andvoObject

You can refer to the following code to execute this query

Using Mybatis-Plus' QueryWrapper simplifies SQL construction and avoids the problem of misspelling keywords
Suppose you already have the corresponding VO class, which contains all the properties in the above query result and their Getter/Setter methods

You can refer to the following code:

// Create a QueryWrapper objectQueryWrapper&lt;UserVO&gt; queryWrapper = new QueryWrapper&lt;&gt;();

// Set the field to query("bs_user.id", "bs_user.mobile", "bs_user.username", "bs_user.password", 
    "bs_user.enable_state", "ss_user_social_security.user_id", 
    "ss_user_social_security.enterprises_pay_social_security_this_month", 
    "ss_user_social_security.enterprises_pay_the_provident_fund_this_month", 
    "ss_user_social_security.participating_in_the_city_id", 
    "ss_user_social_security.social_security_type", "ss_user_social_security.household_registration_type", 
    "ss_user_social_security.social_security_base", "ss_user_social_security.industrial_injury_ratio");

// Add association table("ss_user_social_security", "bs_user.id = ss_user_social_security.user_id");
("ss_company_settings", "bs_user.company_id = ss_company_settings.company_id");

// Add query conditions("ss_company_settings.company_id", 1);

// Call the service layer method to execute queryList&lt;UserVO&gt; userList = (queryWrapper);

In this code, we use the QueryWrapper object to build SQL statements.
By calling methods such as select and join, we can set the fields to query and add the association table.
Finally, use eq and other methods to set the query conditions.
Finally, the list method is called to execute the query and the result is stored in a List object and returned.
Note that the VO class and service call methods in the above code should be replaced according to specific needs.

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.