How do I merge two SELECT queries with different WHERE clauses - sql

Question

I'm trying to write query on two different selects with different WHERE clause and using GROUP BY.
I browsed for examples but mine is different since I have multiple fields for SELECT.
Here is example data:
-- drop table #temp_counts;
create table #temp_counts(
report_date smalldatetime not null,
Emp_id varchar(10) not null,
source_system varchar(10) not null
)
Insert into #temp_counts values ('2021-05-02 00:00:00', '12411', 'ABC');
Insert into #temp_counts values ('2021-05-02 00:00:00', '56421', 'ABC');
Insert into #temp_counts values ('2021-05-02 00:00:00', '45411', 'ABC');
Insert into #temp_counts values ('2021-05-02 00:00:00', '75411', 'ABC');
Insert into #temp_counts values ('2021-05-02 00:00:00', '13245', 'XYZ');
Insert into #temp_counts values ('2021-05-02 00:00:00', '66245', 'XYZ');
Insert into #temp_counts values ('2021-05-02 00:00:00', '77245', 'XYZ');
Insert into #temp_counts values ('2021-05-02 00:00:00', '98245', 'XYZ');
Insert into #temp_counts values ('2021-05-02 00:00:00', '34245', 'XYZ');
Insert into #temp_counts values ('2021-05-02 00:00:00', '29245', 'XYZ');
Insert into #temp_counts values ('2021-05-03 00:00:00', '14524', 'ABC');
Insert into #temp_counts values ('2021-05-03 00:00:00', '17824', 'ABC');
Insert into #temp_counts values ('2021-05-03 00:00:00', '32524', 'ABC');
Insert into #temp_counts values ('2021-05-03 00:00:00', '16724', 'XYZ');
Insert into #temp_counts values ('2021-05-03 00:00:00', '19924', 'XYZ');
Insert into #temp_counts values ('2021-05-03 00:00:00', '89424', 'XYZ');
Insert into #temp_counts values ('2021-05-03 00:00:00', '48324', 'XYZ');
Insert into #temp_counts values ('2021-05-03 00:00:00', '16000', 'XYZ');
Insert into #temp_counts values ('2021-05-04 00:00:00', '18724', 'ABC');
Insert into #temp_counts values ('2021-05-04 00:00:00', '12904', 'XYZ');
Insert into #temp_counts values ('2021-05-05 00:00:00', '12074', 'ABC');
Insert into #temp_counts values ('2021-05-05 00:00:00', '12784', 'XYZ');
Insert into #temp_counts values ('2021-05-05 00:00:00', '12324', 'XYZ');
Insert into #temp_counts values ('2021-05-05 00:00:00', '75124', 'XYZ');
These are the queries I would like to merge:
select count(*) emp_count, report_date , 'ABC' source_system from #temp_counts
where source_system = 'ABC'
group by report_date
order by report_date
select count(*) emp_count, report_date , 'XYZ' source_system from #temp_counts
where source_system = 'XYZ'
group by report_date
order by report_date
I tried 2 methods as under:
--Method 1
select fir.emp_count, fir.report_date, fir.source_system from
(select count(*) emp_count, report_date , 'ABC' source_system from #temp_counts
where source_system = 'ABC') as fir
inner join
(select count(*) emp_count, report_date , 'XYZ' source_system from #temp_counts
where source_system = 'XYZ') as sec
on fir.report_date = sec.report_date
group by fir.report_date
order by fir.report_date
--Method 2
select count(*) emp_count, report_date , 'ABC' source_system from #temp_counts
where source_system = 'ABC'
UNION ALL
select count(*) emp_count, report_date , 'XYZ' source_system from #temp_counts
where source_system = 'XYZ'
group by report_date
order by report_date
Both give Error:
Msg 8120, Level 16, State 1, Line 61
Column '#temp_counts.report_date' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
Please guide

Answer 1

seems like you just want to group by report_date and source_system:
select count(*) emp_count, report_date , source_system
FROM #temp_counts
group by report_date, source_system
order by source_system,report_date
if you want to have result for specific source systems then you can combine conditions:
select count(*) emp_count, report_date , source_system
FROM #temp_counts
where source_system in ('ABC', 'XYZ')
group by report_date, source_system
order by source_system,report_date
you can change order by to show rows in the order you want to show
just to illustrate how to use union :
select count(*) emp_count, report_date , source_system from #temp_counts
where source_system = 'ABC'
group by report_date
union all
select count(*) emp_count, report_date , source_system from #temp_counts
where source_system = 'XYZ'
group by report_date
order by source_system, report_date