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SUBSTR functions

The SUBSTR functions (SUBSTR, SUBSTRB, and SUBSTRC) return a portion of string, beginning at a specified position in the string. The functions vary in how they calculate the length of the substring to return.

Return Value

The return value is the same data type as string.

Syntax

{SUBSTR | SUBSTRB | SUBSTRC }(char, position [, substring_length ])

Parameters

string

A text expression that is the base string from which the substring is created.

position

The position at which the first character of the returned string begins.

substring_length

The length of the returned string. SUBSTR calculates lengths using characters as defined by the input character set. SUBSTRB uses bytes instead of characters. SUBSTRC uses Unicode complete characters.

When you do not specify a value for this argument, then the function returns all characters to the end of string. When you specify a value that is less than 1, the function returns NA.

Examples

Retrieving a Character Substring

The following example returns several specified substrings of "abcdefg".

SHOW SUBSTR('abcdefg',3,4) 
cdef

SHOW SUBSTR('abcdefg',-5,4) 
cdef

Retrieving a Substring Using Bytes

Assume a double-byte database character set.

SHOW SUBSTRB('abcdefg',5,4.2) 
cd