What is a NULL value? What are the pros and cons of using NULLS?

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Is it mandatory to use DCLGEN? If not, why would you use it at all?

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What is the difference between nvl and coalesce?

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What is a DBRM, PLAN ?

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How are write I/Os from the buffer pool executed?

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SET is the ANSI standard for variable assignment, SELECT is not. SET can only assign one variable at a time, SELECT can make multiple assignments at once. If assigning from a query, SET can only assign a scalar value. If the query returns multiple values/rows then SET will raise an error. SELECT will assign one of the values to the variable and hide the fact that multiple values were returned (so you'd likely never know why something was going wrong elsewhere - have fun troubleshooting that one) When assigning from a query if there is no value returned then SET will assign NULL, where SELECT will not make the assignment at all (so the variable will not be changed from it's previous value) As far as speed differences - there are no direct differences between SET and SELECT. However SELECT's ability to make multiple assignments in one shot does give it a slight speed advantage over SET.

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Which component is used to execute the sql statements?

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why db2 is called as universal database?what is the storage capacity of db2v9 n what are the advantages of db2

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What is JOIN and different types of JOIN.

2 Answers   IBM,

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Outputs of explain are with matchcols = 0. What does this signify?

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What is the difference between using bind () and rebind () methods of naming class?

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Explain about rct in db2?

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