Introduction to new Oracle11g Functions

Summary of new Oracle11g functions: ISNULL () function syntax ISNULL (check_expression, replacement_value) parameter check_expression

Summary of new Oracle 11g functions: ISNULL () function syntax ISNULL (check_expression, replacement_value) parameter check_expression

Summary of new Oracle 11g functions:

ISNULL () function

Syntax ISNULL (check_expression, replacement_value)

Parameters

Check_expression

Whether the expression is NULL is checked. Check_expression can be of any type.

Replacement_value

The expression returned when check_expression is NULL. Replacement_value must be of the same type as check_expresssion.

Return type

Returns the same type as check_expression.

Note

If check_expression is not NULL, the value of this expression is returned; otherwise, the value of replacement_value is returned.

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Nvl () function

Returns a non-null value from two expressions.

Syntax

NVL (eExpression1, eExpression2)

Parameters

EExpression1, eExpression2

If the calculation result of eExpression1 is null, NVL () returns eExpression2. If the calculation result of eExpression1 is not null, eExpression1 is returned. EExpression1 and eExpression2 can be any data type. If both eExpression1 and eExpression2 are null values, NVL () returns. NULL ..

Return Value Type

Numeric, currency, logical, or null

It indicates that when null or null values are not supported, NVL () can be used to remove null values in the calculation or operation.

Select nvl (a. name, 'blank ') as name from student a join school B on a. ID = B. ID

Note: The two parameters must be of the same type.