Oracle's NVL and SQL Server IsNull

Oracle's NVL and SQL Server IsNull

Grammar

ISNULL (Check_expression, Replacement_value)   

Parameters
Check_expression
An expression that will be checked for null. Check_expression can be of any type.
Replacement_value
The expression that will be returned when check_expression is null. Replacement_value must have the same type as check_expresssion.

return type
Returns the same type as check_expression.

Notes
If Check_expression is not NULL, the value of the expression is returned, otherwise Replacement_value is returned.

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NVL () function

Returns a non-null value from two expressions.

Grammar

NVL (EExpression1, EExpression2)

Parameters
EExpression1, EExpression2

If the eExpression1 evaluates to a null value, NVL () returns EEXPRESSION2. If the EExpression1 evaluates to a value other than NULL, the EExpression1 is returned. EExpression1 and EExpression2 can be any data type. If the result of both EExpression1 and EExpression2 is null, then NVL () returns. Null..

return value type
character, date, datetime, numeric, currency, logical, or null values

Description
You can use NVL () to remove null values from a calculation or operation in cases where null values are not supported or if NULL values do not matter.

Select NVL (a.name, ' empty ') as name from student a joins school B on A.id=b.id

Note: Two parameter types to match

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Oracle's NVL and SQL Server IsNull