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POSearching for a row with a certain insert value, then comparing a value in that row with an insert value
 

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  1. POSearching for a row with a certain insert value, then comparing a value in that row with an insert value
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    <p>I am trying to create an update trigger that checks the quantity of a product in stock over how much someone is ordering and displays a message if not enough of that product is in stock. </p> <p>It's letting me create the trigger but when testing, it displays an error "Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=,...."</p> <p>I'm not really understanding how it's returning more than one value as I have it searching for the particular row with the product ID that matches the inserted value first. I then have it comparing the UnitsInStock from the inserted value.</p> <p>Here's what I have so far:</p> <pre><code>CREATE TRIGGER tr_check_qty ON OrderDetails FOR UPDATE AS DECLARE @ProductID int, @Quantity int SELECT @ProductID = ProductID, @Quantity = Quantity FROM inserted WHERE @ProductID = ( SELECT ProductID FROM Products ) IF @Quantity &gt; ( SELECT UnitsInStock FROM Products ) BEGIN PRINT 'Not enough product in stock' ROLLBACK TRANSACTION END </code></pre>
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    1. USArion
    1. USSerenity
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    1. COYour trigger is broken - you're assuming that `inserted` only contains one row, which is *not* a correct assumption in general. (Triggers run once per *statement*, not once per *row*)
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      1. POSearching for a row with a certain insert value, then comparing a value in that row with an insert value
      1. USDamien_The_Unbeliever
 

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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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