How to modify the field in mysql to be non-null

In mysql, you can use the "ALTER TABLE" statement and the "NOT NULL" keyword to modify the field to be non-null. When modifying the table, a non-null constraint will be set for the field. The syntax is "ALTER TABLE table name CHANGE COLUMN Field name field name data type NOT NULL;".

The operating environment of this tutorial: windows7 system, mysql8 version, Dell G3 computer.

mysql Modify the field to be non-null

If you forget to set the non-null constraint for the field when creating the table, you can also modify the table. Addition of non-null constraints.

The syntax format for setting non-empty constraints when modifying the table is as follows:

ALTER TABLE <数据表名>
CHANGE COLUMN <字段名>
<字段名> <数据类型> NOT NULL;

Example

Modify the data table tb_dept4, and the specified location cannot be empty

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