CODEWITHSUNDEEP
sqlsql-serverdatabase
neoneclectica
neoneclectica

Reputation: 5

How to Check If A Row Is In Multiple Tables

I’m looking to create a program that checks if data from one row is in two different tables already, and fails if it finds them so it doesn’t create duplicate rows in a table.

Currently I have

If NOT EXISTS (SELECT 1 FROM table_a)

Which works to stop it from duplicating rows in table a, but I want it to not be able to insert a row if the data is also already in table b. What would be the best way to achieve this?

Upvotes: 0

Views: 230

Answers (2)

Venkataraman R
Venkataraman R

Reputation: 12969

You can use NOT EXISTS with union all also.

IF NOT EXISTS(
SELECT 1 FROM Table_a WHERE condition
UNION ALL
SELECT 1 FROM Table_b WHERE condition
.
.
.
)
BEGIN
-- Your logic 
END

Upvotes: 0

Serg
Serg

Reputation: 22811

You can check a number of tables with a condition kind of NOT EXISTS (SELECT 1 FROM table_a WHERE ..) AND NOT EXISTS (SELECT 1 FROM table_b WHERE ..)

Upvotes: 1

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