How to query fields that are not empty in mysql

Mysql query field is not empty method: 1. Use the "select * from table_name where id "";" statement to query; 2. Use "select * from table_name where id != "" ;" statement query.

The operating environment of this tutorial: windows10 system, mysql8.0.22 version, Dell G3 computer.

How to query fields that are not empty in mysql

1. Query that the fields are not empty

select * from table where id <> "";
select * from table where id != "";

# #2. The query is empty

select * from table where id ="";
select * from table where isNull(id);

If the field is of type char or varchar, it is OK to use id=""; if the field is of type int, it is better to use isNull.

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