instr1
This function is used to return the position of substring str2 in string str1.
Similar function: instr. The instr function is used to return the index of substr that appears earliest in str. However, instr does not support specifying the start search position and matching times.
Syntax
instr1(string <str1>, string <str2>[, bigint <start_position>[, bigint <nth_appearance>]])
Parameters
|
Parameter |
Mandatory |
Type |
Description |
|---|---|---|---|
|
str1 |
Yes |
STRING |
Target string to be searched for If the value is of the BIGINT, DOUBLE, DECIMAL, or DATETIME type, the value is implicitly converted to the STRING type for calculation. For other types of values, an error is reported. |
|
str2 |
Yes |
STRING |
Substring to be matched If the value is of the BIGINT, DOUBLE, DECIMAL, or DATETIME type, the value is implicitly converted to the STRING type for calculation. For other types of values, an error is reported. |
|
start_position |
No |
BIGINT |
Sequence number of the character in str1 the search starts from. The default start position is position 1 (position of the first character). If this parameter is set to a negative number, the search starts from the end to the beginning of the string, and the last character is -1. |
|
nth_appearance |
No |
BIGINT |
Position of str2 that is matched for the nth_appearance time in str1. If the value is of another type or is less than or equal to 0, an error is reported. |
Return Values
The return value is of the BIGINT type.
- If str2 is not found in str1, 0 is returned.
- If str2 is an empty string, the matching is always successful.
- If the value of str1, str2, start_position, or nth_appearance is NULL, NULL is returned.
Example Code
The value 10 is returned.
select instr1('Tech on the net', 'h', 5, 1);
The value 2 is returned.
select instr1('abc', 'b');
The value NULL is returned.
select instr('abc', null);
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