核心代码 –下面我演示下MySQL中的排序列的实现–测试数据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.r
核心代码
–下面我演示下MySQL中的排序列的实现
–测试数据
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 SELECT
1;
–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 score
FROM 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 |
+——+——+——-+
