A case study of pits sorted by mybatis-plus QueryWrapper
This article mainly introduces the relevant knowledge of the pit case analysis of mybatis-plus QueryWrapper sorting, the content is detailed and easy to understand, the operation is simple and fast, and it has a certain reference value. I believe you will gain something after reading this mybatis-plus QueryWrapper ranking pit case analysis article. Let's take a look at it.
Pit sorted by QueryWrapper
It can be summed up into the above two sentences.
Conditional constructor QueryWrapper
Let's take a few more examples to delve into the use of the conditional constructor QueryWrapper:
Case one
Check for employees surnamed Li with birth dates ranging from 1993-02-09 to 1994-04-09
Sql implementation:
SELECT * FROM t_employee WHERE DATE_FORMAT (birthday,'%Y-%m-%d') > = '1993-02-09' AND DATE_FORMAT (birthday,'%Y-%m-%d') = '1993-02-09' AND DATE_FORMAT (birthday,'%Y-%m-%d') wq.isNotNull ("email"). Eq ("gender", "female"); List employeeList = employeeMapper.selectList (queryWrapper); System.out.println (employeeList);} case three
Query employees surnamed Li and whose mailbox is not empty or female.
Sql implementation:
SELECT * FROM t_employee WHERE NAME LIKE 'Lee%' AND (email IS NOT NULL OR gender = 'female')
Mp implementation:
/ * query employees surnamed Li and whose mailbox is not empty or female * sql:SELECT * FROM t_employee WHERE NAME LIKE'Li% 'AND (email IS NOT NULL OR gender =' female') * / @ Testpublic void selectByQueryWrapper5 () {QueryWrapper queryWrapper=new QueryWrapper (); / / QueryWrapper queryWrapper2=Wrappers.query (); queryWrapper.likeRight ("name", "Li") .and (wq- > wq.isNotNull ("email"). Or (). Eq ("gender", "female")) List employeeList = employeeMapper.selectList (queryWrapper); System.out.println (employeeList);} case four
The employees whose salary is less than or equal to 3500 are displayed in the order of age, according to the order of age, which belongs to department No. 1 and 2, and whose salary is less than or equal to 3500.
Sql implementation:
SELECT * FROM t_employee WHERE salary
