记录:
ID | NAME | VALUE
---|-------|-------
1 | ALPHA | 5
2 | ALPHA | 7 //comment: [2 times positive numbers]
3 | ALPHA | -4
4 | ALPHA | 3 //comment: [1 times positive numbers]
5 | ALPHA | -2
6 | ALPHA | -3
7 | ALPHA | 9
8 | ALPHA | 3 //comment: [2 times positive numbers]
9 | ALPHA | -2
10 | ALPHA | -6
我需要知道连续多少次我有一个正数,所以在这种情况下我们有: 2(连续正数) 1(连续正数) 2(连续正数)
我想要的最终结果是用表格显示输出,告诉我表格中有多少时间我们有1个连续数字,2个连续数字,3个连续数字,......
所以像这样的表:
表格结构:
consecutive number
value
数据:
1 | 1 (we have 1 times, 1 consecutive numbers)
2 | 2 (we have 2 times, 2 consecutive numbers)
3 | 0 (we have 0 times, 3 consecutive numbers)
答案 0 :(得分:2)
SELECT peak as consecutive_number, COUNT(*) AS value
FROM (
SELECT IF(value <= 0 AND @counter > 0, @counter, NULL) AS peak, @counter := IF(value <= 0, 0, @counter+1) AS counter
FROM (SELECT *
FROM (SELECT value
FROM mytable
ORDER BY id) x
UNION ALL
SELECT -1) x -- in case last row is positive
CROSS JOIN (SELECT @counter := 0) var
) x
WHERE peak IS NOT NULL
GROUP BY peak
答案 1 :(得分:2)
试试这个:
SELECT x consecutive_numbers,
count(*) how_many_times
FROM (
SELECT y, max( x ) x
FROM (
SELECT
if( value < 0, @x:=0, @x:=@x+1 ) x,
if( value < 0, @y:=@y+1, @y ) y,
value
FROM table1
CROSS JOIN (
select @x:=0, @y:=0
) var
ORDER BY id
)q
WHERE value >= 0
GROUP BY y
) qq
GROUP BY x
;
演示: - &gt; http://www.sqlfiddle.com/#!2/75fa7/8