计算不同的ID

Question

我试图计算其最后状态不等的表格的ID＆＃39;被叫＆＃39;

Table1 ╔═════════╦════════╦══════════╗ ║ q_log_id║ q_id ║ q_status ║ ╠═════════╬════════╬══════════╣ ║ 1 ║ 1 ║ Waiting ║ ║ 2 ║ 1 ║ Waiting ║ ║ 3 ║ 1 ║ Called ║ ║ 4 ║ 2 ║ Waiting ║ ║ 4 ║ 2 ║ Waiting ║ ║ 5 ║ 3 ║ Waiting ║ ║ 5 ║ 3 ║ Waiting ║ ╚═════════╩════════╩══════════╝

所以，计数应该返回2.我对查询不好，所以我需要一些帮助。我尝试过与众不同，但它仍然不适合我。

Answer 1

您可以使用窗口分析函数row_number来执行此操作，您可以在q_log_id上执行订单并对q_id列上的行进行分区 并获取最后一行并检查状态是否为“

”

<强> SQL Fiddle

with cte
as
(
select * , row_number() over ( partition by q_id order by q_log_id desc) as rn
from table1
)
select count(q_id)
from cte
where rn =1
and q_status !='Called'

Answer 2

如果您不关心“被叫”是最后一个条目，您可以计算“被叫”从未出现过的q_id值。

SELECT COUNT(1)
FROM
(SELECT q_id
   FROM table1
  GROUP BY q_id
  HAVING MAX(CASE WHEN q_status ='Called' THEN 1 END) IS NULL
) AS v

这是因为查询

SELECT q_id,MAX(CASE WHEN q_status='Called' THEN 1 END)
  FROM table1
 GROUP BY q_id

如果'Called'永远不与q_id

相关联，则

给出NULL

Q_ID    MAX(CASE WHEN Q_STATUS='CALLED' THEN 1 END)
1       1
2       (null)
3       (null)

Answer 3

SELECT COUNT(DISTINCT q_id) AS Count
FROM table1
WHERE q_id IN (
    SELECT q_id
    FROM table1
    GROUP BY q_id
    HAVING MIN(q_status)<> 'Called'
)