SQL statement when the query condition is blank, all data will be queried by default. If it is not blank, the query will be performed according to the condition

SQL Statement to query all data by default when the query condition is empty , If it is not blank, the query will be performed according to the conditions _Chastelovee The blog of -CSDN Blog _sql If it is not empty, query as a condition         Recently do web When I met a problem , When querying list data , There will be multiple query criteria , Some query criteria have data , Some query criteria are empty , When a query condition is blank, all data under this field will be queried by default , In this way SQL How to write query statements ？ I found it on the Internet , Found this way of writing ：select * from surface where ( Field = Conditions or Conditions ='')        This article SQL Statement means when the condition is not empty SQL Statement is equivalent to ：sehttps://blog.csdn.net/Chstelove/article/details/111873922

 

SELECT * FROM student_test WHERE ( Field  LIKE '% Conditions %');

SELECT * FROM student_test WHERE (sex LIKE '%F%') AND (math LIKE '%%');