The default is 0, which returns the starting position of the pattern in the target.
A value of 1 returns the starting position of the next character following the pattern match.
SQL>
SQL> SELECT REGEXP_INSTR('This is a test','a',1,2,0) position
2 FROM dual;
POSITION
----------
0
SQL>
18.2.REGEXP_INSTR |
| 18.2.1. | Regexp_Instr returns the location (beginning) of a pattern in a given string |
| 18.2.2. | REGEXP_INSTR(x, pattern [, start [, occurrence [, return_option [, match_option]]]]) searches for pattern in x. |
| 18.2.3. | Regexp_Instr |
| 18.2.4. | Parameters is a field that may be used to define how one wants the search to proceed: |
| 18.2.5. | Find the 's' and ignore case. |
| 18.2.6. | The simplest regular expression matches letters, letter for letter |
| 18.2.7. | SELECT REGEXP_INSTR('Two is bigger than One','One') where_it_is |
| 18.2.8. | Occurrence refers to the first, second, third, etc., occurrence of the pattern in S. The default is 1 (first). |
| 18.2.9. | Return-option returns the position of the start or end of the matched string. |
| 18.2.10. | The Return-option is set to 1 to indicate the end of the found pattern |
| 18.2.11. | Returns the position of the second occurrence that matches the regular expression s[[:alpha:]]{3} starting at position 1: |
| 18.2.12. | Returns the position of the second occurrence that matches the letter o starting at position 10 using REGEXP_INSTR() |
| 18.2.13. | Specify any series of letters and find matches, just like INSTR |
| 18.2.14. | regexp_instr(comments, '[^ ]+', 1, 9) > 0 |