How can I join these two select queries into one query? - oracle

Question

this is my first time posting, so I am sure I will get a number of things wrong. Do not hesitate to correct me and I will do everything I can to clarify.
In Oracle SQL Developer, I am trying to take two separate SELECT statements and combine them to get one row of results. Unfortunately, because this is sensitive data, I am unable to give any results from the statements individually, but instead, just the SQL statements themselves. I suspect I should be able to join these two on the field "emplid" but just cannot get there. Any help is greatly appreciated! Here is the code below, please mind the syntax :)
1st Select statement is giving me a list of people that were paid in 2017:
SELECT DISTINCT C.COMPANY,
C.EMPLID,
C.SSN
FROM PS_PAY_CHECK C
WHERE TO_CHAR(C.CHECK_DT,'YYYY') = '2017'
AND C.COMPANY IN ('001','054','076')
ORDER BY C.COMPANY, C.EMPLID
And 2nd Select statement would be a list of the deductions taken for the employees that were identified in the first statement:
SELECT G.EMPLID, G.DEDCD,
CASE
WHEN DC.DED_CLASS IN ('A','B','T')
THEN G.DED_ADDL_AMT
ELSE 0
END AS "EEAmt",
CASE
WHEN DC.DED_CLASS NOT IN ('A','B','T')
THEN G.DED_ADDL_AMT
ELSE 0
END AS "ERAmt",
DC.DED_CLASS,
G.DED_ADDL_AMT,
G.GOAL_AMT
FROM PS_GENL_DEDUCTION G,
PS_DED_CLASS_VW DC
WHERE G.EFFDT =
(SELECT MAX(G_ED.EFFDT)
FROM PS_GENL_DEDUCTION G_ED
WHERE G.EMPLID = G_ED.EMPLID
AND G.COMPANY = G_ED.COMPANY
AND G.DEDCD = G_ED.DEDCD
AND G_ED.EFFDT <= SYSDATE
)
AND ( G.DEDUCTION_END_DT IS NULL
OR G.DEDUCTION_END_DT > SYSDATE)
AND ( G.GOAL_AMT = 0.00
OR G.GOAL_AMT <> G.GOAL_BAL)
AND G.DED_ADDL_AMT > 0
AND DC.PLAN_TYPE = '00'
AND DC.DEDCD = G.DEDCD
AND DC.EFFDT =
(SELECT MAX(V1.EFFDT)
FROM PS_DED_CLASS_VW V1
WHERE V1.PLAN_TYPE = DC.PLAN_TYPE
AND V1.DEDCD = DC.DEDCD
)
AND G.EMPLID = 'XXXXXX'
Ideally, what I'd like to do is put in a value in place of 'XXXXXX' and get one row of data with the two combined statements.
Thanks everyone!

Answer 1

To do this, we stick each SELECT statement into a subquery and give that subquery an alias to refer to in the main queries select statement:
SELECT t1.*, t2.*
FROM
(
SELECT DISTINCT C.COMPANY,
C.EMPLID,
C.SSN
FROM PS_PAY_CHECK C
WHERE TO_CHAR(C.CHECK_DT,'YYYY') = '2017'
AND C.COMPANY IN ('001','054','076')
ORDER BY C.COMPANY, C.EMPLID
) t1
INNER JOIN
(
SELECT G.EMPLID, G.DEDCD,
CASE
WHEN DC.DED_CLASS IN ('A','B','T')
THEN G.DED_ADDL_AMT
ELSE 0
END AS "EEAmt",
CASE
WHEN DC.DED_CLASS NOT IN ('A','B','T')
THEN G.DED_ADDL_AMT
ELSE 0
END AS "ERAmt",
DC.DED_CLASS,
G.DED_ADDL_AMT,
G.GOAL_AMT
FROM PS_GENL_DEDUCTION G,
PS_DED_CLASS_VW DC
WHERE G.EFFDT =
(SELECT MAX(G_ED.EFFDT)
FROM PS_GENL_DEDUCTION G_ED
WHERE G.EMPLID = G_ED.EMPLID
AND G.COMPANY = G_ED.COMPANY
AND G.DEDCD = G_ED.DEDCD
AND G_ED.EFFDT <= SYSDATE
)
AND ( G.DEDUCTION_END_DT IS NULL
OR G.DEDUCTION_END_DT > SYSDATE)
AND ( G.GOAL_AMT = 0.00
OR G.GOAL_AMT <> G.GOAL_BAL)
AND G.DED_ADDL_AMT > 0
AND DC.PLAN_TYPE = '00'
AND DC.DEDCD = G.DEDCD
AND DC.EFFDT =
(SELECT MAX(V1.EFFDT)
FROM PS_DED_CLASS_VW V1
WHERE V1.PLAN_TYPE = DC.PLAN_TYPE
AND V1.DEDCD = DC.DEDCD
)
AND G.EMPLID = 'XXXXXX'
) t2 ON
t1.empid = t2.empid
We just treat each derived table/subquery as it's own table and join them on empid. You can tweak the SELECT statement at the top as needed.
This is similar to creating a view for both sql statements and then referencing the views in a third sql statement.
An alternative way of doing this is to use CTE (Common Table Expressions) to house the separate sql. There's no performance advantage here, but you might find it easier to read.
WITH t1 as
(
SELECT DISTINCT C.COMPANY,
C.EMPLID,
C.SSN
FROM PS_PAY_CHECK C
WHERE TO_CHAR(C.CHECK_DT,'YYYY') = '2017'
AND C.COMPANY IN ('001','054','076')
ORDER BY C.COMPANY, C.EMPLID
),
t2 AS
(
SELECT G.EMPLID, G.DEDCD,
CASE
WHEN DC.DED_CLASS IN ('A','B','T')
THEN G.DED_ADDL_AMT
ELSE 0
END AS "EEAmt",
CASE
WHEN DC.DED_CLASS NOT IN ('A','B','T')
THEN G.DED_ADDL_AMT
ELSE 0
END AS "ERAmt",
DC.DED_CLASS,
G.DED_ADDL_AMT,
G.GOAL_AMT
FROM PS_GENL_DEDUCTION G,
PS_DED_CLASS_VW DC
WHERE G.EFFDT =
(SELECT MAX(G_ED.EFFDT)
FROM PS_GENL_DEDUCTION G_ED
WHERE G.EMPLID = G_ED.EMPLID
AND G.COMPANY = G_ED.COMPANY
AND G.DEDCD = G_ED.DEDCD
AND G_ED.EFFDT <= SYSDATE
)
AND ( G.DEDUCTION_END_DT IS NULL
OR G.DEDUCTION_END_DT > SYSDATE)
AND ( G.GOAL_AMT = 0.00
OR G.GOAL_AMT <> G.GOAL_BAL)
AND G.DED_ADDL_AMT > 0
AND DC.PLAN_TYPE = '00'
AND DC.DEDCD = G.DEDCD
AND DC.EFFDT =
(SELECT MAX(V1.EFFDT)
FROM PS_DED_CLASS_VW V1
WHERE V1.PLAN_TYPE = DC.PLAN_TYPE
AND V1.DEDCD = DC.DEDCD
)
AND G.EMPLID = 'XXXXXX'
)
SELECT t1.*, t2.*
FROM t1 INNER JOIN t2 ON
t1.empid = t2.empid

Answer 2

Basically you do something like
select blah, blah.. (your second query )
AND G.EMPLID IN ( SELECT DISTINCT C.COMPANY,
C.EMPLID,
C.SSN
FROM PS_PAY_CHECK C
WHERE TO_CHAR(C.CHECK_DT,'YYYY') = '2017'
AND C.COMPANY IN ('001','054','076')
)
So basically I have used your first query in you second query. I removed the DISTINCT, as its not needed.
I hope that makes sense.