SELECT ROW_NUMBER()OVER(ORDER BY id), x, y, id FROM coordonnees ORDER BY id
I’m trying to return the row number of each row (the table named coordonnees
with 3 columns: id
, x
, y
), but this code doesn’t work
The error is:
Syntax error near ‘(ORDER BY id), x, y, id
on database : MYSQL 5.7.9
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Answer
Apparently, MySQL 5.7 doesn’t support ROW_NUMBER()
. However, I found a novel solution that will emulate it at this site.
SELECT @row_num := IF(@prev_value=c.id,@row_num+1,1) AS RowNumber ,c.x ,c.y ,c.id ,@prev_value := c.id FROM coordonnees c, (SELECT @row_num := 1) x, (SELECT @prev_value := -1) y ORDER BY c.id
There are a few caveats, though:
- The
@row_num
variable must be set before the@prev_value
variable. - The first field in the
ORDER BY
must be the field that you are partitioning by. - The default value assigned to the
@prev_value
variable must not exist in the partition by field.