How to modify a field to be non-empty by mysql

This article mainly introduces how mysql modifies the field to be non-empty, which has certain reference value. Interested friends can refer to it. I hope you will gain a lot after reading this article. Let Xiaobian take you to understand it together.

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

Operating environment of this tutorial: Windows 7 system, MySQL8 version, Dell G3 computer.

mysql modified field is non-empty

If you forgot to set non-null constraints for fields when you created the table, you can also add non-null constraints by modifying the table.

The syntax for setting non-null constraints when modifying tables is as follows:

ALTER TABLE CHANGE COLUMN NOT NULL;

example

Modify the data table tb_dept4. The specified location cannot be empty.

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