RANK(), DENSE_RANK(), and ROW_NUMBER() in MySQL 8.0
In MySQL 8.0, RANK(), DENSE_RANK(), and ROW_NUMBER() are window functions used to assign sequential numbers to rows based on a specified order. They differ in how they handle ties (rows with the same values in the ORDER BY clause).
Assigns a unique sequential number to each row in the result set.
Does not consider ties; every row gets a distinct number.
Sequence always increments by 1.
Assigns the same rank to rows with identical values in the ORDER BY clause (ties).
Leaves gaps in the ranking sequence after ties.
Useful when you want to reflect tie positions explicitly.
Assigns the same rank to tied rows, similar to RANK().
Does not leave gaps in the ranking sequence.
Useful when you want consecutive ranking numbers even with ties.
ROW_NUMBER() always gives unique numbers; ignores ties.
RANK() gives tied rows the same rank and skips subsequent numbers.
DENSE_RANK() gives tied rows the same rank but does not skip numbers.
In summary: Use ROW_NUMBER() for unique row numbering, RANK() when you need tie-aware ranking with gaps, and DENSE_RANK() when you need tie-aware ranking without gaps in the sequence.