SQL Server built-in functions
Coalesce()
It is A function Is Very Much Useful at Run time When We Have
Multi Value Attribute in a Table.
If U Consider below facts placed in a employee table With Id,
Name, ph_no, Alt_no, Office no.
id
|
Name
|
Ph_ no
|
Alt_ no
|
Office no
|
101
|
Albert
|
999999
|
456453
|
321333
|
102
|
khan
|
null
|
null
|
123455
|
103
|
victor
|
112121
|
null
|
null
|
104
|
lovely
|
null
|
null
|
1897321
|
Above Employee table may have single value are three values
if it have single value then it fill null values with remaining attributes
When We Retrieve The Number from employee table That Number Should Not be Null value To get not null
value from employee table We Use Coalesce() Function It Returns First Encountered Not Null
Value from employee table
select id , name ,coalesce(Ph_no,Alt_no,Office_no) as contact number from employee
it returns
id
|
Name
|
Contact number
|
101
|
Albert
|
999999
|
102
|
khan
|
123455
|
103
|
victor
|
112121
|
104
|
lovely
|
1897321
|
Thank you
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