Summary of case usage in SQL Server

First build the table and insert the data statement:

Use Student

Go

CREATE TABLE Score

(

School number nvarchar (10),

Course nvarchar (10),

Score int

)

Go

INSERT into Score values (' 0001 ', ' language ', 87);

INSERT into Score values (' 0001 ', ' math ', 79);

INSERT into Score values (' 0001 ', ' English ', 95);

INSERT into Score values (' 0002 ', ' language ', 69);

INSERT into Score values (' 0002 ', ' math ', 84);

INSERT into Score values (' 0001 ', ' language ', 95);

Case when usage one:

Case simple expression that determines the result by comparing the expression to a simple set of expressions.

Select School Number,

SUM (case when course = ' language ' then accomplishment else 0 end) as language,

SUM (case when course = ' math ' then result else 0 end) as mathematics,

SUM (case when course = ' English ' then result else 0 end) as English

From Score

Group BY School Number

Case when usage two:

Case search expression that determines the result by calculating a set of Boolean expressions.

Select study number, score,

Case results

When then ' Liang '

When then ' Liang '

When then ' excellent '

When then ' in '

Else ' bad ' end as test

From Score

Above for my understanding of case, if there is a mistake I hope to criticize, thank you!

Note: Each case corresponds to a column of data