T_sql programming assignment, branching statements, looping

We often use assignments, loops, branching statements, etc. in C #

Today, let's look at what we used in C # to put in SQL.

Creating variables

Creating a value-type variable in C # is simple int A; that's fine.

Sql:declare @a int; -This is the creation of an int type variable a in SQL

Be sure to remember to create a variable in SQL before you must add @

Assign value

Set @a = 123

Now is the assignment of a to a value of 123.

Assign also add @

Output

Output in VS you remember that, Console.write/console.writeline?

That's the output in SQL, which is divided into two types

First Kind

Select @a--this is only mapped to the result set, note that the mapping

The second Kind

Print @a-This is the output in SQL

Branch statements

It's still if..........else.

But slightly changed.

1 Declare @a int2 Declare @b int3 4 Set @a = 1235 Set @b = 4566 7 8 if @a > @b9 beginTen     Select 'wrong' One End A Else - begin -     Select 'the' the End

The output of the time remember that the full selection of SQL will not be the same as vs automatically give you a sentence to execute SQL is you choose which sentence he gave you to execute which sentence

So create variables and assign variables to be selected for execution, or SQL will throw you a contemptuous look at you, else if the same

Cycle

The loops are slightly different.

1  Declare @a int2   3  Set @a = 14   5   while @a <= Ten6  begin7       Select @a8       Select @a = @a + 19       Ten  End

But the loop turns out this way.

If that's the case

1  Declare @a int2   3  Set @a = 14   5   while @a <= Ten6  begin7       8       Select @a+19       Select @aTen        One  End

So that's the infinite loop.

Don't ask me why, I just restarted the SQL

Because I didn't notice where the pause key was.

Yes, look at how much CPU and memory can occupy.

Next again.

T_sql programming assignment, branching statements, looping