SQL isnull () function Conversion

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Replace with the specified replacement valueNull.

 

Syntax

 

 

 
  Isnull(Check_expression, replacement_value)
 

 

 

 

Parameters

 

Check_expression

 

Will be checkedNull.Check_expressionIt can be of any type.

 

Replacement_value

 

InCheck_expressionIsNullWill return the expression.Replacement_valueMust beCheck_expresssionHas the same type.

 

Return type

 

Returns andCheck_expressionThe same type.

 

Note

 

IfCheck_expressionNotNullOtherwise, the value of the expression is returned.Replacement_value.

 

Example

 

A.SetIsnullAndAVGUse together

 

The following example shows the average price of all books.$10.00ReplaceTitlesTablePriceAllNull.

 

  UsePubs
Go
Select AVG(Isnull(Price, $10.00))
FromTitles
Go
 

 

The following is the result set:

 

--------------------------

14.24

 

(1 row (s) affected)

B.UseIsnull

 

The following example showsTitlesSelect the title, type, and price for all the books in the table. If the price of a title isNull, The price displayed in the result set is0.00.

 

  Use  Pubs
  Go  
  Select     Substring  (Title,  1  ,  15  )  As  Title, Type As  Type,
  Isnull  (Price,  0.00  )  As  Price
  From  Titles
  Go 

 

The following is the result set:

 

Title Type Price

-----------------------------------------------------

The busy execut business 19.99

Cooking with Co Business 11.95

You can combat business 2.99

Straight talk a business 19.99

Silicon Valley mod_cook 19.99

The Gourmet mic mod_cook 2.99

The psychology undecided 0.00

But is it user popular_comp 22.95

Secrets of sili popular_comp 20.00

Net etiquette popular_comp 0.00

PC phobic psychology 21.59

Is anger the en psychology 10.95

Life without Fe fig 7.00

Prolonged data psychology 19.99

Emotional secur psychology 7.99

Onions, leeks, trad_cook 20.95

Policty years in trad_cook 11.95

Sushi, anyone? Trad_cook 14.99

 

(18 row (s) affected)

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