SQL - 当行包含特定数字时计算行

Question

例如，如果我有一个名为ticket的表，其中包含一个名为ticketid的列。故障单ID包含数字，有时数字会出现多次，因为故障单可能有多次更新。如何创建一个变量来输出ticketid的次数？

例如：

ticketid：7
ticketid：7 timeoccured：2

Answer 1

SELECT ticketid, count(*) AS timesoccured
FROM   tickets
-- WHERE  ticketid = 7  -- to just get the one ...
GROUP  BY 1;

GROUP BY 1是GROUP BY ticket_id的简写语法 Start by reading the manual here.

通常，列ticketid在tickets表中是唯一的。您的命名约定或数据模型遵循可疑的逻辑。

Answer 2

假设TicketId不为NULL，您应该使用：

SELECT TicketId, COUNT(TicketId) AS TicketIdCount
FROM [Table]
GROUP BY TicketId

Answer 3

SELECT COUNT(*), ticketid 
FROM tickets 
GROUP BY ticketid;

Answer 4

如果您只想重复的门票使用having

select ticketid, count(*)
from tickets
group by 1
having count(*) > 1