SUBSTR Function in MySQL

In MySQL, the SUBSTR() function is used to extract a substring from a string. It takes three arguments:-

1. The original string.

2. The starting position from where the substring extraction should begin (1-based index).

3. Optionally, the length of the substring to be extracted.

The syntax is as follows:-

SUBSTR(original_string, start_position, length) 

If the length argument is not provided, SUBSTR() returns all characters from the start_position to the end of the string.

Example:-

SELECT SUBSTR('Hello World', 1, 5); -- Output: 'Hello'

SELECT SUBSTR('Hello World', 7);    -- Output: 'World'

These examples illustrate how the SUBSTR() function works in MySQL to extract substrings from a given string.

Here are five frequently asked questions (FAQs) about the SUBSTR() function in MySQL:-

1. What does the SUBSTR() function do in MySQL?

   - The SUBSTR() function is used to extract a substring from a string in MySQL. It allows you to specify the starting position and optionally the length of the substring to be extracted.

2. Is the index for the starting position in SUBSTR() zero-based or one-based in MySQL?

   - The index for the starting position in the SUBSTR() function is one-based, meaning the first character of the string is at position 1, the second character is at position 2, and so on.

3. What happens if the starting position provided to SUBSTR() exceeds the length of the string?

   - If the starting position provided to SUBSTR() is greater than the length of the string, MySQL returns an empty string.

4. Can the SUBSTR() function be used with columns from database tables in MySQL?

   - Yes, the SUBSTR() function can be applied to columns from database tables in MySQL. It allows you to extract substrings from the values stored in those columns.

5. Is there a difference between SUBSTR() and `SUBSTRING()` in MySQL?

   - No, there is no difference between SUBSTR() and SUBSTRING() in MySQL. They are interchangeable and can be used interchangeably to achieve the same result of extracting substrings from strings.