在存储过程SQL Server 2005中选择“计数交叉”选项卡

Question

I have a view name vStudent (Room_No, Study_Date, Student_ID, Student Sex, Nationality) I want to create a stored procedure in SQL Server by scenario below:

i have some data:

• Room_No (1,2,3,4,..)
• Study_Date (08-02-2012,..)
• Student_ID (001,002,003,...)
• Student_Sex(Male, Female)
• Nationality(Cambodian, Thailand, Chinese)

in my stored procedure i want to:

• Select Room_No
• Select Study_Date
• Select Count Student_Sex separated by Male and Female
• Select Count Nationality separated by Cambodian, Thailand, Chinese
• Group BY Room_No, Study_Date
• Filter between Study_Date

the result in report should be show as below:

Room No Study Date  Male    Female  Cambodian   Thailand    Chinese
1   2/7/2012    1   0   1   0   0
2   2/8/2012    0   2   0   1   1
3   2/9/2012    1   2   1   2   0
4   2/10/2012   3   1   2   1   1

I think this can be done by use cross tab in stored procedure, but i don't know to do.

Please help. thanks.

Answer 1

You are going to need to use dynamic SQL to figure out which columns you want to display, unless you know the full set of possible nationality values.

DECLARE @start DATETIME, @end DATETIME;

SET @start = '20120802';
SET @end = '20120802';

DECLARE @sql NVARCHAR(MAX);

SET @sql = N'SELECT Room_No, Study_Date, 
    Male = SUM(CASE WHEN Student_Sex = ''Male'' THEN 1 ELSE 0 END),
    Female = SUM(CASE WHEN Student_Sex = ''Female'' THEN 1 ELSE 0 END)';

SELECT @sql = @sql + CHAR(13) + CHAR(10) + 
    ',' + Nationality + ' = SUM(CASE WHEN Nationality = ''' 
    + Nationality + ''' THEN 1 ELSE 0 END)' 
FROM dbo.vStudent 
WHERE Nationality IS NOT NULL
GROUP BY Nationality;  

SET @sql = @sql + ' FROM dbo.vStudent
    WHERE Study_Date >= ''' 
        + CONVERT(CHAR(8), @start, 112) + '''
    AND Study_Date < ''' 
        + CONVERT(CHAR(8), DATEADD(DAY, 1, @end), 112) + '''
    GROUP BY Room_No, Study_Date;';

EXEC sp_executesql @sql;

If the set of nationalities is known, then you can simply say:

SELECT 
    Room_No, Study_Date, 
    Male      = SUM(CASE WHEN Student_Sex = 'Male'      THEN 1 ELSE 0 END),
    Female    = SUM(CASE WHEN Student_Sex = 'Female'    THEN 1 ELSE 0 END),
    Cambodian = SUM(CASE WHEN Nationality = 'Cambodian' THEN 1 ELSE 0 END),
    Chinese   = SUM(CASE WHEN Nationality = 'Chinese'   THEN 1 ELSE 0 END),
    Thailand  = SUM(CASE WHEN Nationality = 'Thailand'  THEN 1 ELSE 0 END)
    -- continue other nationalities here 
FROM dbo.vStudent
WHERE Study_Date >= @start
AND Study_Date < DATEADD(DAY, 1, @end)
GROUP BY Room_No, Study_Date;

You could probably do this a little more elegantly with PIVOT , but it really depends on your definition of "elegant." See the docs here .