SQL Server Null Function and Comment. Session 28

Null Functions
ISNULL ()
ISNULL () function is used to replace NULL values.
Syntax:
SELECT column(s) FROM table_name
WHERE ISNULL(column_name);
NULLIF ()
The NULLIF function takes two arguments. If the two arguments are equal, then NULL is returned. Otherwise, the first argument is returned.
Syntax:
SELECT column(s), NULLIF(expression1, expression2)
FROM table_name;
SELECT col1,col2, IFNULL(col3, value_to_be_replaced) FROM tableName;
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