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UNION should be used with caution
Rule description
- UNION should be used with caution
Non-compliant Code Example
SELECT Name, Phone FROM Employee UNION --Non compliant code (Use UNION ALL instead of Union) SELECT Name, Phone From Customer;
SELECT Name, Phone FROM Customer WHERE StateCode=0015 UNION --Non compliant code (No need to use Union clause, get entries by changing Where clause) SELECT Name, Phone From Customer WHERE StateCode=0028;
Compliant Code Example
SELECT Name, Phone FROM Employee UNION ALL --Compliant code (UNION ALL is used) SELECT Name, Phone From Customer;
SELECT Name, Phone From Customer WHERE StateCode=0028 OR StateCode=0015; --Compliant code