MySQL NULL Values

We have seen the SQL SELECT command along with the WHERE caluse to fetch data from a MySQL table, but when we try to give a condition, which compares the field or column value to NULL, it does not work properly.
To handle this type of situation, MySQL provides three operators-

• IS NULL –  This operator returns true, if the column value is NULL.
• IS NOT NULL – This operator  returns true, if the column value is not NULL.
• <=> – This operator compares values, which (unlike the = operator) is true even for two NULL values.

The conditions involving NULL are special. You can’t  use = NULL or !=NULL to look for NULL values in columns. Such comparisons always fail because it is  impossible to tell wheteher they are true or not. Some- times, even NULL=NULL fails.
To look for columns that are or are not NULL, use IS NULL or IS NOT NULL.

For Examples

Table tblstudents

Handling NULL values
Ex:

OUTPUT

Ex:

OUTPUT

NOTE :

You can see  that = and != do not work with the NULL Values.