: . , ( . " " 4), . (null), .
, , : Is Null
. CustomerID Orders , . , :
Is Not Null
( ) . - . , Nz ().
Nz () . ( , ) . , , Access . , Nz () 0 Quantity:
Nz([Quantity], 0)
0 Nz (), , , :
Nz([Quantity])
, , . , , , . :
OrderItemCost: [Quantity] * [Price]
, Quantity . . , . , OrderItemCost . , OrderItemCost , . , .
Nz (): OrderItemCost: Nz([Quantity]) * Nz([Price])
, Nz () , - . , ("Not Entered" ) , :
Name: Nz([FirstName] & [LastName], "[Not Entered]")
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, , . 143 Orders, 143 . . .
:
■ ;
■ , ;
■ , ;
■ ;
■ , ;
■ , .
, , (totals query). , .
:
1. , → → (Create → Other → Query Design).
2. (Show Table) (Close).
Products Boutique Fudge.
3. , .
Price, : Price , .
4. → → (Query Tools → Show/Hide → Totals).
Access ( Total) .
5. . .
. .
■ ( , . .). . . 7.7 .
■ . . , .
■ . (WHERE). ( , , , WHERE , SQL, . " " 6). , Access .
, , .
(. 7.8) Price : Max, Min Avg.
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 |
. 7.8. : Price . , , . : , , Boutique Fudge
. 7.7 , StDev Var .
7.7.
| , | |
| Sum | |
| Avg | |
| Min | |
| Max | |
| Count | ( , ) |
| First | |
| Last |
, . , CategoryID, , :
=3
, CategoryID 3 ( Candies ()).
, , , .
