How to Get the Record Index (Row Number) in a MySQL Table?

Getting the Record Index in a MySQL Table

In MySQL, tables often contain a large number of records. It can be useful to have a column that contains the record index, or row position, for each row in a table. This can be used for a variety of purposes, such as ranking users or displaying the position of a particular record in a sequence.

Solution

To generate a column containing the record index, you can use a combination of user-defined variables and a join statement. Here is an example:

SELECT  l.position, 
        l.username, 
        l.score,
        @curRow := @curRow + 1 AS row_number
FROM    league_girl l
JOIN    (SELECT @curRow := 0) r;

In this query:

• The @curRow variable is initialized to 0 using the (SELECT @curRow := 0) statement.
• The JOIN statement ensures that the @curRow variable is incremented by 1 for each row in the league_girl table.
• The row_number column contains the record index for each row in the table.

Example Usage

Consider the following league_girl table:

position	username	score
1	a	10
2	b	25
3	c	75
4	d	25
5	e	55
6	f	80
7	g	15

The following query returns the record index, username, and score for all rows in the league_girl table with a score greater than 50:

SELECT  l.position, 
        l.username, 
        l.score,
        @curRow := @curRow + 1 AS row_number
FROM    league_girl l
JOIN    (SELECT @curRow := 0) r
WHERE   l.score > 50;

The output of this query is:

position	username	score	row_number
3	c	75	1
5	e	55	2
6	f	80	3

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