This function is used to return the start or end position of the substring that matches a specified pattern for the occurrence time, starting from start_position in the string source.
Syntax
regexp_instr(string <source>, string <pattern>[,bigint <start_position>[, bigint <occurrence>[, bigint <return_option>]]])
Parameters
Parameter |
Mandatory |
Type |
Description |
|---|---|---|---|
source |
Yes |
STRING |
Source string |
pattern |
Yes |
STRING |
Constant or regular expression of the STRING type. Pattern to be matched. If the value of this parameter is an empty string, an error is reported. |
start_position |
No |
BIGINT |
Constant of the BIGINT type. Start position of the search. If it is not specified, the default value 1 is used. |
occurrence |
No |
BIGINT |
Constant of the BIGINT type. It indicates the specified number of matching times. If this parameter is not specified, the default value 1 is used, indicating that the first occurrence position is searched. |
return_option |
No |
BIGINT |
Constant of the BIGINT type. This parameter indicates the location to be returned. The value can be 0 or 1. If this parameter is not specified, the default value 0 is used. If this parameter is set to a value of another type or a value that is not allowed, an error message is returned. The value 0 indicates that the start position of the match is returned, and the value 1 indicates that the end position of the match is returned. |
Return Values
The return value is of the BIGINT type. return_option indicates the start or end position of the matched substring in source.
- If the value of pattern is an empty string, an error is reported.
- If the value of start_position or occurrence is not of the BIGINT type or is less than or equal to 0, an error is reported.
- If the value of source, pattern, start_position, occurrence, or return_option is NULL, NULL is returned.
Example Code
The value 6 is returned.
select regexp_instr('a1b2c3d4', '[0-9]', 3, 2);
The value NULL is returned.
select regexp_instr('a1b2c3d4', null, 3, 2);