这里有一种方法,这种方法虽然没有规模特别好......
DROP TABLE IF EXISTS my_table;
CREATE TABLE my_table
(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
,value1 INT NOT NULL
,value2 CHAR(1) NOT NULL
);
INSERT INTO my_table VALUES
(1,1,'A'),
(2,1,'B'),
(3,2,'A'),
(4,3,'A'),
(5,3,'A'),
(6,3,'B'),
(7,3,'A');
SELECT x.*
, COUNT(y.id) rt
FROM my_table x
JOIN my_table y
ON y.value1 = x.value1
AND y.value2 = x.value2
AND y.id <= x.id
GROUP
BY x.id;
+----+--------+--------+----+
| id | value1 | value2 | rt |
+----+--------+--------+----+
| 1 | 1 | A | 1 |
| 2 | 1 | B | 1 |
| 3 | 2 | A | 1 |
| 4 | 3 | A | 1 |
| 5 | 3 | A | 2 |
| 6 | 3 | B | 1 |
| 7 | 3 | A | 3 |
+----+--------+--------+----+
。 ..这是一个更快的方法...
SET NAMES utf8;
SELECT x.id
, value1
, value2
, x.n
FROM
(SELECT id
, CASE WHEN value1 = @prev1 AND value2 = @prev2 THEN @i:[email protected]+1 ELSE @i:=1 END n
, @prev1:=value1 value1
, @prev2:=value2 value2
FROM my_table
, (SELECT @i:=1, @prev1:=0,@prev2:='') vars
ORDER
BY value1
, value2
) x
ORDER
BY id;
+----+--------+--------+------+
| id | value1 | value2 | n |
+----+--------+--------+------+
| 1 | 1 | A | 1 |
| 2 | 1 | B | 1 |
| 3 | 2 | A | 1 |
| 4 | 3 | A | 1 |
| 5 | 3 | A | 2 |
| 6 | 3 | B | 1 |
| 7 | 3 | A | 3 |
+----+--------+--------+------+
此表没有PRIMARY KEY,这可能会证明问题进一步在路上......只是说' – Strawberry
@Strawberry:你说得对。实际的表具有它。我试图保持最低限度的例子。不过,我现在意识到,那么订单是未定义的,所以我添加了id列。 – texnic