Difference between revisions of "DD Class11"
esse quam videri
(→Sql Functions) |
(→Sql Aggregate Functions) |
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| Line 12: | Line 12: | ||
Aggregate functions are determinate. They will return the same value given the same dataset. | Aggregate functions are determinate. They will return the same value given the same dataset. | ||
| − | AVG | + | *AVG |
| − | MIN | + | *MIN |
| − | CHECKSUM | + | *CHECKSUM |
| − | SUM | + | *SUM |
| − | CHECKSUM_AGG | + | *CHECKSUM_AGG |
| − | STDEV | + | *STDEV |
| − | COUNT | + | *COUNT |
| − | STDEVP | + | *STDEVP |
| − | COUNT_BIG | + | *COUNT_BIG |
| − | VAR | + | *VAR |
| − | GROUPING | + | *GROUPING |
| − | VARP | + | *VARP |
| − | MAX | + | *MAX |
<sql> | <sql> | ||
Revision as of 03:49, 11 April 2007
Contents
Review Data Diagram for final
- are they normal?
- can the design acomplish your goals?
- are they over engineered?
Sql Aggregate Functions
They perform a calculation on a set to values and return a single value. Aggregate functions are determinate. They will return the same value given the same dataset.
- AVG
- MIN
- CHECKSUM
- SUM
- CHECKSUM_AGG
- STDEV
- COUNT
- STDEVP
- COUNT_BIG
- VAR
- GROUPING
- VARP
- MAX
<sql> SELECT MAX(PricePerPound) as MaxPrice from CheesePrice
SELECT AVG(PricePerPound) as AvgPrice from CheesePrice
SELECT COUNT(CheeseID) as Count from CheesePrice </sql>
Sub Query
Course adder example
http://iam.colum.edu/dd/classsource/class8/student.aspx
SQL Subquery
<sql>SELECT CourseID, CourseName, CourseNumber FROM Course WHERE (
CourseID not in
(
SELECT CourseID FROM StudentsCourses_vw WHERE StudentID = @StudentID
)
) </sql>
Uploader/Email
Mappath
Server.Mappath
upload permissions
HomeWork
Web Skeleton of your site
Demostate one feature
