MySQL is Clause
MySQL is clause is used in conjuction with Where clause to check the NULL values in any column. The general syntax of MySQL is clause is as follows
Syntax
SELECT column1, column2, ....... FROM tableName WHERE column1 is NULL
sample Database to show the working of IS clause
+-------+---------+--------+-------+-------+---------+--------+ | admno | name | stream | marks | grade | fees | gender | +-------+---------+--------+-------+-------+---------+--------+ | 101 | rakesh | sci | 96.56 | A | 1850.35 | F | | 102 | udit | sci | 56.50 | B | 1850.35 | M | | 103 | mohit | bio | 46.50 | C | 1980.90 | M | | 104 | mannat | human | 67.50 | A | 1420.15 | F | | 105 | unnati | comm | 77.50 | B | 1650.75 | F | | 106 | nikunj | sci | 79.50 | A | 1850.35 | M | | 107 | pushkar | comm | 54.20 | C | 1650.75 | M | | 108 | pratham | comm | 84.80 | A | 1650.75 | M | | 109 | mohit | comm | 64.80 | B | 1650.75 | M | | 110 | urshavi | bio | 96.80 | A | 1980.90 | M | | 111 | punya | comm | 86.56 | B | 1650.75 | F | | 112 | vipul | comm | NULL | A | 1650.75 | M | +-------+---------+--------+-------+-------+---------+--------+
NULL values -means the absence of a value, can’t be checked using the normal comparison operator. The example demonstrates the same
mysql> select * from student
-> where marks = NULL;
Empty set (0.00 sec)
Now display all the records where marks of the student are not present ie NULL
mysql> select * from student -> where marks IS NULL; +-------+-------+--------+-------+-------+---------+--------+ | admno | name | stream | marks | grade | fees | gender | +-------+-------+--------+-------+-------+---------+--------+ | 112 | vipul | comm | NULL | A | 1650.75 | M | +-------+-------+--------+-------+-------+---------+--------+ mysql> select * from student -> where marks IS NOT NULL; +-------+---------+--------+-------+-------+---------+--------+ | admno | name | stream | marks | grade | fees | gender | +-------+---------+--------+-------+-------+---------+--------+ | 101 | rakesh | sci | 96.56 | A | 1850.35 | F | | 102 | udit | sci | 56.50 | B | 1850.35 | M | | 103 | mohit | bio | 46.50 | C | 1980.90 | M | | 104 | mannat | human | 67.50 | A | 1420.15 | F | | 105 | unnati | comm | 77.50 | B | 1650.75 | F | | 106 | nikunj | sci | 79.50 | A | 1850.35 | M | | 107 | pushkar | comm | 54.20 | C | 1650.75 | M | | 108 | pratham | comm | 84.80 | A | 1650.75 | M | | 109 | mohit | comm | 64.80 | B | 1650.75 | M | | 110 | urshavi | bio | 96.80 | A | 1980.90 | M | | 111 | punya | comm | 86.56 | B | 1650.75 | F | +-------+---------+--------+-------+-------+---------+--------+ 11 rows in set (0.00 sec)