SQL Cross Table instance

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SQL Cross Table instance

A very simple thing, see a lot of friends on the internet asked "how to implement the Cross table?" ", here's an example I wrote, the database is based on SQL SERVER 2000.

-- ======================================================

--cross-table instance

-- ======================================================

Build table:

Running in Query Analyzer:

CREATE TABLE [Test] (

[ID] [int] IDENTITY (1, 1) not NULL,

[Name] [nvarchar] (m) COLLATE chinese_prc_ci_as NULL,

[Subject] [nvarchar] (m) COLLATE chinese_prc_ci_as NULL,

[Source] [Numeric] (18, 0) Null

) on [PRIMARY]

Go

INSERT into [test] ([Name],[subject],[source]) VALUES (n ' John ', n ' language ', 60)

INSERT into [test] ([Name],[subject],[source]) VALUES (n ' Dick ', n ' math ', 70)

INSERT into [test] ([Name],[subject],[source]) VALUES (n ' Harry ', N ' English ', 80)

INSERT into [test] ([Name],[subject],[source]) VALUES (n ' Harry ', n ' math ', 75)

INSERT into [test] ([Name],[subject],[source]) VALUES (n ' Harry ', n ' language ', 57)

INSERT into [test] ([Name],[subject],[source]) VALUES (n ' Dick ', n ' language ', 80)

INSERT into [test] ([Name],[subject],[source]) VALUES (n ' John ', N ' English ', 100)

Go



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Implementation of crosstab statements:

--For: The number of columns in the crosstab is OK

Select Name,sum (case subject when ' math ' then source else 0 end) as ' mathematics ',

SUM (case subject when ' English ' then source else 0 end) as ' English ',

SUM (case subject when ' language ' then source else 0 end) as ' language '

From Test

Group BY name





--For: The number of columns in the crosstab is indeterminate

DECLARE @sql varchar (8000)

Set @sql = ' Select Name, '



Select @sql = @sql + ' sum (case subject when ' +subject+ ' "

Then source else 0 end) as ' +subject+ ', '

From (select distinct subject from test) as a



Select @sql = Left (@sql, Len (@sql)-1) + ' from test group by name '

EXEC (@sql)

Go



Run Result:

450) this.width=450 "o:title=" SQL >