如何正确 select 这个分组数据？

Question

First of all, sorry for the generic title, I don't know how exactly to word the question I have.

I am working with a legacy database and can't make changes to the schema, so I'm forced to work with what I've got.

Table setup (columns):

1. Id (a normal int id)
2. UniqueId (a column that holds the uniqueIds for each location)
3. status (a varchar column that can contain one of three status's, 'completed', 'failed', 'Attention')
4. Count (an int column that represents how many users fell into each status

Example data:

    UniqueId    Status  Count
679FCE83-B245-E511-A42C-90B11C2CD708    completed   64
679FCE83-B245-E511-A42C-90B11C2CD708    Attention   1
679FCE83-B245-E511-A42C-90B11C2CD708    failed  101
4500990D-F516-E411-BB09-90B11C2CD708    completed   100
4500990D-F516-E411-BB09-90B11C2CD708    Attention   17
4500990D-F516-E411-BB09-90B11C2CD708    failed  516
557857BD-6B46-E511-A42C-90B11C2CD708    completed   67
557857BD-6B46-E511-A42C-90B11C2CD708    Attention   4
557857BD-6B46-E511-A42C-90B11C2CD708    failed  103

What I am trying to do is select all of the records, grouped by uniqueId, with a separate column for each of the status's containing their individual counts. The results would look something like this...

UniqueId, count(completed), count(failed), count(Attention)
679FCE83-B245-E511-A42C-90B11C2CD708     64     101     1
4500990D-F516-E411-BB09-90B11C2CD708     100     516     17
557857BD-6B46-E511-A42C-90B11C2CD708     67     103     4

I'm sure I'm missing something basic with this, but I can't seem to find the words to Google my way out of this one.

Could someone push me in the right direction?

Answer 1

You can use conditional aggregation:

select uniqueid, 
       sum(case when status = 'Completed' then count else 0 end) as completed,
       sum(case when status = 'Failed' then count else 0 end) as failed, 
       sum(case when status = 'Attention' then count else 0 end) as attention
from t
group by uniqueid;