SUBSTR returns a substring, specified by y and z,
of x.
>>-SUBSTR(x,y-+----+-)----------------------------------------->< '-,z-'
- x
- String expression. It specifies the string from which the substring is extracted. If x is not a string, it is converted to character.
- y
- Expression that is converted to FIXED BINARY(31,0). y specifies the starting position of the substring in x.
- z
- Expression that is converted to FIXED BINARY(31,0). z specifies the length of the substring in x. If z is zero, a null string is returned. If z is omitted, the substring returned is position y in x to the end of x.
The STRINGRANGE condition is raised if z is negative or if the values of y and z are such that the substring does not lie entirely within the current length of x. It is not raised when y = LENGTH(x)+1 and z = 0. For an example of the SUBSTR built-in function, see SEARCH.