notnull Use sql command to modify a field in the data table to be non-null not null statement

ALTER TABLE table1 ALTER COLUMN [name] varchar(60) NULL;
table1 table name
name field name Why add [], because name is a sql keyword and an error will occur due to conflict, just in case.
If an index has been created for the name field, if it needs to be modified, the index must be deleted first to proceed correctly.

The above introduces the notnull statement of using sql command to modify a field in the data table to be non-null, including the notnull content. I hope it will be helpful to friends who are interested in PHP tutorials.