Explain about SQL COALESCE..

Answer:

This COALESCE function is used to return a value which is the first non-null expression among all its arguments.
If all the arguments are NULL, in that case COALESCE will return NULL.
It is also used to display any other value instead of NULL value in the result.

Example:

SELECT Name, COALESCE(Business_Phone, Cell_Phone, Home_Phone) Contact_Phone 

FROM Contact_Info; 

Result:

Name  Contact_Phone 

Jeff   531-2531 

Laura  772-5588 

Peter  594-7477