what is difference between "Primary key" and "Unique key"?

4 Answers   PreVator,

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What is the main difference between a UNION statement and a UNION ALL statement? 1. A UNION statement eliminates duplicate rows; a UNION ALL statement includes duplicate rows. 2. A UNION statement can be used to combine any number of queries; a UNION ALL statement can be used to combine a maximum of two queries. 3. A UNION statement can only combine queries that have parallel fields in the SELECT list; a UNION ALL statement can combine queries with differing SELECT list structures. 4. A UNION statement cannot be used with aggregate functions; a UNION ALL statement can be used with aggregate functions. 5. There is no difference between the two statements; they are interchangeable.

2 Answers   Saman Bank, Sonata,

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What do you mean by rowid?

0 Answers  

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Table Order_Name has a column Order_Date which gives the date & Time at which the order is passed.Find the table to write a query to find out the latest order.

5 Answers   Thomson,

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How to fetch common records from two tables?

1 Answers  

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what is difference between procedure and function

10 Answers   MCN Solutions, Wipro,

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Explain character-manipulation functions?

0 Answers  

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what is the use of double ampersand (&&) in sql queries?

0 Answers  

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How to run sql statements through the web interface?

0 Answers  

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What is pl sql in dbms?

0 Answers  

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How do I order by ascending in sql?

0 Answers  

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Write the order of precedence for validation of a column in a table ?

2 Answers  

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