Full introduction to new oracle 11g functions

The check_expression parameter of the ISNULL () function syntax ISNULL (check_expression, replacement_value) of the new oracle 11G function will be checked for a NULL expression. Check_expression can be of any type. Replacement_value returns the expression when check_expression is NULL. Replacement_value must be of the same type as check_expresssion. Return 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. The ---------------------------------------------------------------------------------------------- nvl () function returns a non-null value from two expressions. Syntax NVL (eExpression1, eExpression2) parameter 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 .. If null or null values are not supported, you can use NVL () to remove the null value in the calculation or operation. [SQL] 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.