LENGTH is applied to either a character string expression or a bit string expression and returns the number of characters in the result.
Because all built-in data types are implicitly converted to strings, this function can act on all built-in data types.
LENGTH ( { CharacterExpression | BitExpression } )
-- returns 20 VALUES LENGTH('supercalifragilistic') -- returns 1 VALUES LENGTH(X'FF') -- returns 4 VALUES LENGTH(1234567890)