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 be written

View Usage: SELECT * from view name

3.SQL programming

Define variable: DECLARE @ variable name data type

Variable assignment: SET @ variable name = value

Output: Print variable or string

Check the car table with the name of the BMW two words

DECLARE @name varchar (20)

Set @name = ' BMW '

SELECT * from car where Name like '% ' [email protected]+ '% '

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 price for all cars: ' +cast (@price as varchar (20))

If ... else usage, 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

15-07-20 Database--indexed view programming