Syntax of Logical Operator ALL : 

Return type of ALL operator is boolean. It returns TRUE when the comparison specified is TRUE for all pairs(scalar_expression, x)  where x is a value in the single-column set otherwise it returns FALSE.

Example of  Logical Operator ALL :

Example 1 : Using all operator with subquery in a where clause 

SELECT  OrderID, Subtotal

FROM  Order_Subtotals

WHERE  Subtotal > ALL(SELECT SaleAmount

                                         FROM Sales_Totals_by_Amount)

ORDER BY Subtotal DESC

 

Output

OrderID         Subtotal

10865               16387.50

10981               15810.00

11030               12615.05

10889               11380.00

Above query instructs the outer query to select records whose Subtotal is greater than all the values of SaleAmount from Sales_Totals_by_Amount. It means it will reaturn records whose value is greater than the greatest value returned by the subquery.