combine two query results into one with conditions in SQL Server - sql

Question

I have two query to combine two results into one. However; my challenge is to get the second query look into the first query if it doesn't exist in the first query.
I changed my post to the actual query
SELECT Name.CO_ID, Name.FULL_NAME, Name.ID, rpt.date AS StartDate,
vw_Coords.TARGET_ID AS CoordID, vw_RegDirs.TARGET_ID AS
RDID
FROM Name INNER JOIN
Tops_Profile ON dbo.Name.ID = Tops_Profile.ID left
outer JOIN
vw_mz_rpt_leader_log rpt ON Name.CO_ID = rpt.ID LEFT
OUTER JOIN
vw_RegDirs ON Name.CO_ID = vw_RegDirs.CHAPTER LEFT
OUTER JOIN
vw_Coords ON Name.CO_ID = vw_Coords.CHAPTER LEFT OUTER
JOIN
Tops_Chapter ON Tops_Chapter.ID = Name.CO_ID
WHERE (Name.MEMBER_TYPE = 'm') AND (Tops_Profile.LDR = '1') and
LOG_TEXT like '%LEADER Change%'
union
SELECT Name.CO_ID, Name.FULL_NAME, Name.ID,
YEAR(dbo.Tops_Chapter.PST_DATE_LEAD) AS StartDate,
vw_Coords.TARGET_ID AS CoordID, vw_RegDirs.TARGET_ID AS
RDID
FROM Name INNER JOIN
Tops_Profile ON Name.ID = Tops_Profile.ID left outer
JOIN
vw_mz_rpt_leader_log rpt ON Name.CO_ID = rpt.ID LEFT
OUTER JOIN
vw_RegDirs ON Name.CO_ID = vw_RegDirs.CHAPTER LEFT
OUTER JOIN
vw_Coords ON Name.CO_ID = vw_Coords.CHAPTER LEFT OUTER
JOIN
Tops_Chapter ON Tops_Chapter.ID = Name.CO_ID
WHERE (Name.MEMBER_TYPE = 'm') AND (Tops_Profile.LDR = '1')
the scope is if the record exists in the first query don't bring it from second query.

Answer 1

Here's a quick and dirty way...
select *
from
(select id, Name, log.Date
from Name
inner join Log on Name.id = log.id
where log.text_log like '%Leader%'
union
select id, Name, Profile.Date
from Name
inner join profile on Name.id = profile.id
where profile.Leader = '1') d
order by row_number() over(partition by x.id order by x.Date asc)
Note, this doesn't care where John came from, it's simply finding the first occurrence based on the date which seems to be what you want.

Answer 2

You have altered your request. Suddenly both queries select from the same tables and a UNION (or UNION ALL for that matter) doesn't seem a good solution anymore.
There are very few differences between the two queries even. And looking at the whole it boils down to: select records for member_type = 'm' and tp.ldr = 1 and then keep only one record per name, preferredly one with log_text like '%LEADER Change%'. This is mere ranking, as already shown in my other answer. You only need one query to select all records in question and use TOP (1) WITH TIES to keep the best matches per name.
select top(1) with ties
n.co_id,
n.full_name,
n.id,
case when log_text like '%LEADER Change%' then rpt.date else year(tc.pst_date_lead) end
as startdate,
c.target_id as coordid,
rd.target_id as rdid
from name n
inner join tops_profile tp on n.id = tp.id
left outer join vw_mz_rpt_leader_log rpt on n.co_id = rpt.id
left outer join vw_regdirs rd on n.co_id = rd.chapter
left outer join vw_coords c on n.co_id = c.chapter
left outer join tops_chapter tc on tc.id = n.co_id
where n.member_type = 'm'
and tp.ldr = 1
order by row_number() over (
partition by n.id
order by case when log_text like '%LEADER Change%' then 1 else 2 end);
As you said you just want only one record per name, I am using ROW_NUMBER. If you want more, use RANK instead.
It's not clear why you are joining the tops_chapter table. Is log_text a column in that table? (You should use a table qualifier for this column in your query.) If it isn't, then the join is superfluous and you can remove it from your query.

Answer 3

Use row_number and select id's with least date
with cte as
(select id, Name, log.Date
from Name
inner join Log on Name.id = log.id
where log.text_log like '%Leader%'
union all
select id, Name, Profile.Date as log.date
from Name
inner join profile on Name.id = profile.id
where profile.Leader = '1'
) , ct1 as (select id,name,log.date, ROW_NUMBER() over (partition by id order by log.date) rn from cte )
select id,name,log.date from ct1 where rn = 1

Answer 4

where profile.Leader = '1'
and id not in ( select Name.id
from Name
inner join Log
on Name.id = log.id
where log.text_log like '%Leader%' )

Answer 5

You can use NOT EXISTS in the second query to filter out already existing Name records:
select id, Name, log.Date
from Name
inner join Log on Name.id = log.id
where log.text_log like '%Leader%'
union
select n1.id, n1.Name, Profile.Date
from Name as n1
inner join profile on n1.id = profile.id
where profile.Leader = '1' and
not exists (select 1
from Name as n2
inner join Log on n2.id = Log.id
where Log.text_log like '%Leader%' and
n2.id = n1.id and n2.name = n1.name)

Answer 6

The query below finds logdate and profiledate for each name. If there is a logdate, the logdate will be diplayed else the profile date will be displayed. If both don't exist the Name won't be displayed.
select id, Name, coalesce(log.Date,profile.date)
from Name
left join Log on Name.id = log.id and log.text_log like '%Leader%'
left join profile on Name.id = profile.id and profile.Leader = '1'
where coalesce(log.Date,profile.date) is not null

Answer 7

You can add a rank to your two queries. Then per ID you keep the record(s) with the better rank (using ORDER BY with TOP (1) WITH TIES).
select top(1) with ties
id, name, date
from
(
select n.id, n.name, log.date, 1 as rnk
from name n
inner join log on name.id = log.id
where log.text_log like '%Leader%'
union all
select n.id, n.name, profile.date, 2 as rnk
from name n
inner join profile on name.id = profile.id
where profile.leader = '1'
) data
order by rank() over (partition by id order by rnk);