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COALESCE Function in SQL ORACLE Query With Example

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ORACLE/PLSQL: COALESCE FUNCTION The Oracle/PLSQL COALESCE function returns the first non-null expression in the list. If all expressions evaluate to null, then the COALESCE function will return null. The syntax for the Oracle/PLSQL COALESCE function is: coalesce( expr1, expr2, ... expr_n ) PARAMETERS: expr1 to expr_n are the expressions to test for non-null values. EXAMPLE: The COALESCE function can be used in Oracle/PLSQL. You could use the coalesce function in a SQL statement as follows: SELECT COALESCE( address1, address2, address3 ) result FROM suppliers; The above COALESCE function is equivalent to the following IF-THEN-ELSE statement: IF address1 is not null THEN result := address1; ELSIF address2 is not null THEN result := address2; ELSIF address3 is not null THEN result := address3; ELSE result := null; END IF; The COALESCE function will compare each value, one by one. Lets apply the same to emp table. We have some NULL values in comm and mgr columns. but not in any other columns. So lets take a example for this 2 columns. COALESCE(comm,mgr,sal) Here if comm is null, function returns mgr value. If mgr is null it returns sal value! Query used in video: SELECT ename,comm,mgr,sal,COALESCE(comm,mgr,sal) result FROM emp;
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kuhnman (4 years ago)
Worthless video without any audio.

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