Writing SQL INSERT which retrieves its data from two separate related rows - sql

Question

I am writing a SQL script that is to insert a new record using data from two rows that are under the same AccountID.
My table looks like the following:
AccountID | ActivityId | DisplayDetails | TransactionDate | EnvironmentId
============================================================================
1 7 Display1 2015-02-02 00:00:00.000 1
1 8 DisplayThis1 2018-02-02 00:00:00.000 1
1 7 Display2 1999-02-02 00:00:00.000 2
1 8 DisplayThis2 2000-02-02 00:00:00.000 2
My fix is to find find each 7,8 combination and insert a new row with ActivityId 78 that gets the DisplayDetails from ActivityId 7 and TransactionDate from ActivityId 8.
My queries looks like the following:
SELECT *
INTO #ActivityEight
FROM Account A
WHERE A.ActivityId = 8
INSERT INTO #Account (AccountId, ActivityId, DisplayDetails, TransactionDate)
SELECT VL.AccountId, 78, S.DisplayDetails, VL.TransactionDate
FROM #temp2 VL WITH(NOLOCK)
JOIN #ActivityEight S
ON VL.AccountId = S.AccountId
WHERE VL.ActivityId = 7
However when I run SELECT * FROM Account I get a 78 row for each 7 and 8 row, when I should only get 1 78 row per 7 and 8 combination.
AccountID | ActivityId | DisplayDetails | TransactionDate | EnvironmentId
=============================================================================
1 7 Display1 2015-02-02 00:00:00.000 1
1 8 DisplayThis1 2018-02-02 00:00:00.000 1
1 7 Display2 1999-02-02 00:00:00.000 2
1 8 DisplayThis2 2000-02-02 00:00:00.000 2
1 78 DisplayThis1 2015-02-02 00:00:00.000 NULL
1 78 DisplayThis2 2015-02-02 00:00:00.000 NULL
1 78 DisplayThis1 1999-02-02 00:00:00.000 NULL
1 78 DisplayThis2 1999-02-02 00:00:00.000 NULL
I believe I can utilize the EnvironmentId to achieve the desired functionality, but I'm not sure how.
Any help would be appreciated.
Thanks!

Answer 1

I think this will help you
INSERT INTO #Account (AccountId, ActivityId, DisplayDetails, TransactionDate)
SELECT VL.AccountId, 78, S.DisplayDetails, VL.TransactionDate
FROM Account VL WITH(NOLOCK)
JOIN Account S ON VL.AccountId = S.AccountId and VL.EnvironmentId = S.EnvironmentId
WHERE VL.ActivityId = 7 and S.ActivityId = 8