What is SUBSTR functions and rVersion 11.1

SUBSTR functions
Definition:
The Oracle SUBSTR (SUBSTRING) function lets you extract a portion of a string (a 'substring') from a string of characters. 
The SUBSTR functions (SUBSTR, SUBSTRB, SUBSTRC, SUBSTR2, and SUBSTR4) 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.

• SUBSTR calculates lengths using characters as defined by the input character set.
• SUBSTRB calculates lengths using bytes.
• SUBSTRC calculates lengths using Unicode complete characters.
• SUBSTR2 calculates lengths using UCS2 code points.
• SUBSTR4 calculates lengths using UCS4 code points.

Return Value

The return value is the same data type as string.

Syntax

{SUBSTR | SUBSTRB | SUBSTRC | SUBSTR2 | SUBSTR4}(char, position [, substring_length ])

Arguments

string

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

Oracle SUOrVersion 11.1

UBSTR (overload 2)	SUBSTR( STR1 CLOB CHARACTER SET ANY_CS, POS  NUMBER,                -- starting position LEN  NUMBER := 2147483647)  -- number of characters RETURN CLOB CHARACTER SET STR1%CHARSET;
Substring Beginning Of String	SELECT SUBSTR(<value>, 1, <number_of_characters>) FROM DUAL;
	SELECT SUBSTR('Take the first four characters', 1, 4) FIRST_FOUR FROM DUAL;
Substring Middle Of String	SELECT SUBSTR(<value>, <starting_position>, <number_of_characters>) FROM DUAL.
	SELECT SUBSTR('Take the first four characters', 16, 4) MIDDLE_FOUR FROM DUAL;
Substring End of String	SELECT SUBSTR(<value>, <starting_position>) FROM DUAL;
	SELECT SUBSTR('Take the first four characters', 16) SIXTEEN_TO_END FROM DUAL; SELECT SUBSTR('Take the first four characters', -4) FINAL_FOUR FROM DUAL;

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