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Is it possible to select from the result of a union? For example I'm trying to do something like:
SELECT A FROM ( SELECT A, B FROM TableA UNION SELECT A, B FROM TableB ) WHERE B > 'some value' Am I missing anything or making an assumption about how this works? I'm using MSSQL 2005 so any solution will need to conform to what I can do there.
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The UNION operator is used to combine the result-set of two or more SELECT statements. Every SELECT statement within UNION must have the same number of columns. The columns must also have similar data types. The columns in every SELECT statement must also be in the same order.
What Is UNION in SQL? The UNION operator is used to combine the data from the result of two or more SELECT command queries into a single distinct result set. This operator removes any duplicates present in the results being combined.
In SQL, the UNION operator selects rows from two or more tables. If rows of tables are the same, those rows are only included once in the result set. For example, SELECT age FROM Teachers UNION SELECT age FROM Students; Run Code.
You should give alias to your table. So try this:
SELECT A FROM ( SELECT A, B FROM TableA UNION SELECT A, B FROM TableB ) AS tbl WHERE B > 'some value' If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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