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23-01-07, 09:39 PM
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Sql - What does the following query do? SELECT SAL + NVL(COMM,0) FROM EMP;
Sql - What does the following query do? SELECT SAL + NVL(COMM,0) FROM EMP;
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28-01-07, 11:13 PM
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Re: Sql - What does the following query do? SELECT SAL + NVL(COMM,0) FROM EMP;
NVL function is used to substitue a value when a null value present.
In this case, NVL(comm,0) replaces every null value with number 0. <column_value>+NULL sums to NULL. Hence for conviniece, as long as we are logically right, we are in this case trying to add 2 numbers, Hence we are using NVL(comm,0) so that the operation inturn wud be for null values in commission sal+0 which makes sense.
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08-05-08, 07:05 PM
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Re: Sql - What does the following query do? SELECT SAL + NVL(COMM,0) FROM EMP;
NVL function can be used if you want to handle null differently. Generally NVL function is used to replace 'null' value with some other value while querying data.
In the above usage nvl(comm,0) - if 'comm' column value is null, then 0 (zero) is returned. Otherwise, value in 'comm' column is returned. You can also replace the value of that 0 (zero) with any value as required. Ref links - Oracle/PLSQL: NVL Function How to use the nvl function in Oracle Similar - Oracle/PLSQL: NVL2 Function Mini-Tip #2 - NVL2() Oracle Functions Thanks, Krishna
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