Oracle / PLSQL: INSTR4 Function
This Oracle tutorial explains how to use the Oracle/PLSQL INSTR4 function with syntax and examples.
Description
The Oracle/PLSQL INSTR4 function returns the location of a substring in a string, using UCS4 code points.
Syntax
The syntax for the INSTR4 function in Oracle/PLSQL is:
INSTR4( string, substring [, start_position [, th_appearance ] ] )
Parameters or Arguments
- string
- The string to search. string can be CHAR, VARCHAR2, NCHAR, or NVARCHAR2. string can not be CLOB or NCLOB.
- substring
- The substring to search for in string. substring can be CHAR, VARCHAR2, NCHAR, NVARCHAR2, CLOB, or NCLOB.
- start_position
- Optional. The position in string where the search will start. If omitted, it defaults to 1. The first position in the string is 1. If the start_position is negative, the INSTR4 function counts back start_position number of characters from the end of string and then searches towards the beginning of string.
- nth_appearance
- Optional. The nth appearance of substring. If omitted, it defaults to 1.
Returns
The INSTR4 function returns a numeric value. The first position in the string is 1.
If substring is not found in string, then the INSTR4 function will return 0.
If string is NULL, then the INSTR4 function will return NULL.
If substring is NULL, then the INSTR4 function will return NULL.
Note
- See also the REGEXP_INSTR function.
Applies To
The INSTR4 function can be used in the following versions of Oracle/PLSQL:
- Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i, Oracle 8i
Example
Let's look at some Oracle INSTR4 function examples and explore how to use the INSTR4 function in Oracle/PLSQL.
For example:
INSTR4('TechOnTheNet.com', 'e') Result: 2 (the first occurrence of 'e') INSTR4('TechOnTheNet.com', 'e', 1, 1) Result: 2 (the first occurrence of 'e') INSTR4('TechOnTheNet.com', 'e', 1, 2) Result: 9 (the second occurrence of 'e') INSTR4('TechOnTheNet.com', 'e', 1, 3) Result: 11 (the third occurrence of 'e') INSTR4('TechOnTheNet.com', 'e', -3, 2) Result: 9
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