核心代碼
| --下面我演示下MySQL中的排序列的實(shí)現(xiàn)--測(cè)試數(shù)據(jù)CREATE TABLE tb(score INT);INSERT tb SELECT 5 UNION ALL SELECT 4 UNION ALL SELECT 4 UNION ALL SELECT 4 UNION ALL SELECT 3 UNION ALL SELECT 2 UNION ALL SELECT1;--1.row_number式的排序SET @row_number =0;SELECT @row_number := @row_number+1 AS row_number,score FROM tb ORDER BY score DESC ;+------------+-------+| row_number | score |+------------+-------+| 1 | 5 || 2 | 4 || 3 | 4 || 4 | 4 || 5 | 3 || 6 | 2 || 7 | 1 |+------------+-------+--2.dense_rank式的排序SET @dense_rank = 0,@prev_score = NULL;SELECT @dense_rank :=IF(@prev_score=score,@dense_rank,@dense_rank+1) AS decnse_rank, @prev_score := score AS score FROM tb ORDER BY score DESC ; +-------------+-------+| decnse_rank | score |+-------------+-------+| 1 | 5 || 2 | 4 || 2 | 4 || 2 | 4 || 3 | 3 || 4 | 2 || 5 | 1 |+-------------+-------+--3.rank式的排序SET @row=0,@rank=0,@prev_score=NULL;SELECT @row:=@row+1 AS ROW, @rank:=IF(@prev_score=score,@rank,@row) AS rank, @prev_score:=score AS scoreFROM tb ORDER BY score DESC;+------+------+-------+| ROW | rank | score |+------+------+-------+| 1 | 1 | 5 || 2 | 2 | 4 || 3 | 2 | 4 || 4 | 2 | 4 || 5 | 5 | 3 || 6 | 6 | 2 || 7 | 7 | 1 |+------+------+-------+ |
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