How to check if a record already exists before inserting a new one
I'm looking for a simple clean way to make an MS SQL statement that selects all of column1 and column2 from one table, and inserts them into another table as new records, but only if the values for both column1 and column2 do not already exist in the table the insertion is being attempted on. Essentially, I do not want any duplication of values where the value of either column1 OR column2 must contain a unique value, but both do not need to be unique. Hope this is an easy one. Thanks.
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Hi sdstuber. I was hoping to not raise any exceptions at all. Is there one semi complex SQL statement that can accomplish this without errors?
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I saw this which looks like it might do what I want. Does anybody know about this and will it work?
INSERT INTO table ( column1, column2, column3 )
(
SELECT $column1, $column2, $column3
WHERE NOT EXISTS (
SELECT 1
FROM table
WHERE column1 = $column1
AND column2 = $column2
AND column3 = $column3 )
)
I think it's clo9se to what I want but it might not do exactly what I want. I don't fully understand it.
INSERT INTO table ( column1, column2, column3 )
(
SELECT $column1, $column2, $column3
WHERE NOT EXISTS (
SELECT 1
FROM table
WHERE column1 = $column1
AND column2 = $column2
AND column3 = $column3 )
)
I think it's clo9se to what I want but it might not do exactly what I want. I don't fully understand it.
Let us know if you're interested in trying the solution I posted, as I've used it in multiple projects, and can attest that it meets the requirements as stated in this question.
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Thanks guys.
then simply insert the rows and capture exception on duplicates.
you can either ignore or report the attempt as needed.