COMPUTER SCIENCE AND ENGINEERING
SQL
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
Choose the correct query
|
|
SELECT * FROM EMP WHERE NAME=NULL
|
|
|
SELECT * FROM EMP WHERE NAME IS NULL;
|
|
|
SELECT FROM EMP WHERE NAME IS NULL;
|
|
|
SELECT *FROM EMP WHERE NAME IS ‘NULL’;
|
Explanation:
Detailed explanation-1: -The IS NULL condition is used in SQL to test for a NULL value. It returns TRUE if a NULL value is found, otherwise it returns FALSE. It can be used in a SELECT, INSERT, UPDATE, or DELETE statement.
Detailed explanation-2: -The IS NULL constraint can be used whenever the column is empty and the symbol ( ‘ ‘) is used when there is empty value. mysql> SELECT * FROM ColumnValueNullDemo WHERE ColumnName IS NULL OR ColumnName = ‘ ‘; After executing the above query, the output obtained is.
Detailed explanation-3: -SQL IS NULL WHERE IS NULL tests if a column has a NULL value. NULL is a special value that signifies unknown or no value. Testing for NULL with the = operator is not possible.
There is 1 question to complete.