SQL error 1064 - how to fix?

Question

What is this?

SQL query: 

ALTER TABLE `ads` ADD `ad_title` VARCHAR NOT NULL 

MySQL said:  
 #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'NOT NULL' at line 1

Query is generated by phpmyadmin

Answer 1

您没有为VARCHAR分配长度。

Answer 2

The syntax error in this sentence lies in the type definition of the column. It should specify the maximum length of the VARCHAR column.

ALTER TABLE `ads` ADD `ad_title` VARCHAR(10) NOT NULL 

It is working in this sqlfiddle .

See the following example, where length 50 is assigned to columns First_Name and Surname :