15-07-20 Database--indexed view programming

1. Index

Add an index, design the interface, right-click on any column--index/key--tap to add an index

2. View

The view is the virtual table we've queried.

Creating views: Create View name as

SQL query statements--grouping, sorting, in, and so on cannot write view usage: SELECT * from view name

3.SQL programming

A, defining variables: DECLARE @ variable name data type

B, Variable assignment: SET @ variable name = value

C, output: Print variable or string

For example: 1, check the car table name contains the BMW two characters

DECLARE @name varchar set @name = ' BMW ' SELECT * from car where name like '% ' [email protected]+ '% '

Example: 2. Check the average of all cars in the car table and output

DECLARE @price decimal (10,4) Select @price = AVG (price) from car print ' average prices for all cars are: ' +cast (@price as varchar (20))

D, If ... else usage (same as C # usage, just if the condition does not require parentheses, curly braces become the begin ... end...else...bigin...end)

If there is no parenthesis, curly braces are replaced with begin end

If judging condition

Begin the statement to execute

End

Else

Begin the statement to execute

End

Switch case in C # morphing into database usage

DECLARE @ccname varchar (20)

Set @ccname = ' BMW '

SELECT * from Car where Name is like

Case

When @ccname = ' bmw ' Then '% BMW '

When @ccname = ' Audi ' Then '% Audi '

Else '% '

End

Note: Do not write a semicolon or comma after the statement ends

15-07-20 Database--indexed view programming