select instr

`INSTR` is a function commonly used in SQL queries to find the starting position of a substring within a string. It returns the position of the first occurrence of the substring within the string, or 0 if the substring is not found. The syntax for the `INSTR` function is as follows:

INSTR(string, substring, [start_position, [occurrence]])

- `string`: The string in which you want to search for the substring.
- `substring`: The substring you want to find within the string.
- `start_position` (optional): The position in the string where the search should start. If not specified, the search starts from the beginning of the string.
- `occurrence` (optional): The occurrence of the substring to find. If not specified, it defaults to 1.

Here's an example usage:

SELECT INSTR('Hello, World', 'World') AS position;

This query will return the value `8`, as the substring 'World' starts at position 8 within the string 'Hello, World'.