SQL-表子组内的数据透视

Question

I'm using SQL Server 2014 Management Studio and I'm pretty new to SQL. I am trying to find out how to do a pivot within a table sub-group.

I have the following table:

Equipment Name                       Time       Tag1     Tag2
---------------------------------------------------------------
XXX1A                                1:00       10.5      50.5
XXX1A                                1:05       12        70
XXX1A                                1:10       15        100
XXX1B                                1:00       10.6      51
XXX1B                                1:05       12.1      70.5
XXX1B                                1:10       16        101
XXZ1A                                1:00       10.5      50.5
XXZ1A                                1:05       13        80
XXZ1A                                1:10       15        100
XXZ1B                                1:00       10.6      51
XXZ1B                                1:05       12.1      70.5
XXZ1B                                1:10       19        104

XXX is one system and 1A / 1B are equipment within that system.

XXZ is another system and 1A / 1B are equipment within that system.

I need to pivot within the system groups so that the final table looks like this.

System  Time    1A_Tag1  1A_Tag2    1B_Tag1  1B_Tag2
----------------------------------------------------
XXX     1:00    10.5     50.5       10.6     51
XXX     1:05    12       70         12.1     70.5
XXX     1:10    15       100        16       101
XXZ     1:00    10.5     50.5       10.6     51
XXZ     1:05    13       80         12.1     70.5
XXZ     1:10    15       100        19       104

The number of time stamps for each system is always constant and each system has the same number of time stamps.

Thanks for the help

Answer 1

You need to separate the Name and the Tag s first. You can do that by using SUBSTRING and RIGHT . Then just do a conditional aggregation on the result:

WITH CTE AS(
    SELECT *,
        System  = SUBSTRING(EquipmentName, 1, LEN(EquipmentName) - 2),
        Tag     = RIGHT(EquipmentName, 2)
    FROM tbl
)
SELECT
    System,
    Time,
    [1A_Tag1]   = MAX(CASE WHEN Tag = '1A' THEN Tag1 END),
    [1A_Tag2]   = MAX(CASE WHEN Tag = '1A' THEN Tag2 END),
    [1B_Tag1]   = MAX(CASE WHEN Tag = '1B' THEN Tag1 END),
    [1B_Tag2]   = MAX(CASE WHEN Tag = '1B' THEN Tag2 END)
FROM CTE
GROUP BY System, Time
ORDER BY System, Time