Copy data from one table to another iff second table doesn't already contains that data

Question

Could any one help me in writing a MS SQL query to copy rows from one table to another only if table1.Col1 != table2.col1.

I am making a SSIS package to do this procedure so an approach related to it would be very helpful.

Possible duplicate of [SQL Server insert if not exists best practice](http://stackoverflow.com/questions/5288283/sql-server-insert-if-not-exists-best-practice) — Tab Alleman, Jun 14 '16 at 12:30
Have you tried anything? Please show your effort in order for us to help you. — Denn, Jun 14 '16 at 12:39

score 1 · Answer 1 · edited Jun 15 '16 at 10:05

1

1) Slowly Changing Dimension data flow task.

2) Use Lookup.

3) Use Merge.

edited Jun 15 '16 at 10:05

BIDeveloper

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answered Jun 14 '16 at 12:31

sandeep rawat

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score 1 · Answer 2 · answered Jun 14 '16 at 14:09

Simplest way (to me): optionally join (LEFT OUTER JOIN) to the target table (table you're loading into), and use WHERE to confirm that the join fails:

INSERT INTO dbo.MYTARGETTABLE (TARG_COL1, TARG_COL2)
SELECT SRC.[SRC_COL1], SRC.[SRC_COL2]
FROM dbo.MYSOURCETABLE  SRC
    LEFT OUTER JOIN dbo.MYTARGETTABLE  TARG
        ON TARG.[TARG_COL1] = SRC.[SRC_COL1]
WHERE SRC.[SRC_COL1] IS NOT NULL
----this column is only null if the join failed: 
AND TARG.[TARG_COL1] IS NULL

This of course assumes that there are no valid NULLs in the column(s) you join with.

Copy data from one table to another iff second table doesn't already contains that data

2 Answers2