LEFT returns a string that is the result of inserting string x at
the left end of a string with length n and padded on the
right with the character z as needed.
Expression. x must have a computational type and
should have a character type. If not, it is converted to CHARACTER.
n
Expression. n must have a computational type and
should have a character type. If n does not have the attributes
FIXED BINARY(31,0), it is converted to them.
z
Expression. If specified, z must have the type CHARACTER(1)
NONVARYING type.