Notnull using SQL commands to modify a statement in a data table that is not null for a field

Alter TABLE table1 ALTER COLUMN [name] varchar () NULL;
Table1 Table Name
Name field name why add [], because name is the SQL keyword will conflict error, so just in case.
If the name field has already created an index, you must delete the index before you can correct it if you need to modify it.

The above describes the notnull with the SQL command to modify a field in the data table is a non-null NOT NULL statement, including the notnull aspect of the content, I hope the PHP tutorial interested in a friend helpful.

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