Compare two sets of XML data using XQuery in SQL Server

Question

Suppose I store employee data in a xml column in my log table. Sometimes data is also updated in the xml column from a stored procedure.

He

Answer 1

I don't have the exact output you wanted - but at least you get a good comparison of old and new values:

;WITH OldData AS
(
SELECT 
    @XML1.value('(/NewDataSet/Employee/EmpID)[1]', 'int') AS 'EmpID',
    @XML1.value('(/NewDataSet/Employee/Name)[1]', 'varchar(50)') AS 'Name',
    @XML1.value('(/NewDataSet/Employee/DOB)[1]', 'datetime') AS 'DOB',
    @XML1.value('(/NewDataSet/Employee/DeptID)[1]', 'varchar(50)') AS 'DeptID',
    @XML1.value('(/NewDataSet/Employee/Salary)[1]', 'varchar(25)') AS 'Salary'
),
NewData AS
(
SELECT 
    @XML2.value('(/NewDataSet/Employee/EmpID)[1]', 'int') AS 'EmpID',
    @XML2.value('(/NewDataSet/Employee/Name)[1]', 'varchar(50)') AS 'Name',
    @XML2.value('(/NewDataSet/Employee/DOB)[1]', 'datetime') AS 'DOB',
    @XML2.value('(/NewDataSet/Employee/DeptID)[1]', 'varchar(50)') AS 'DeptID',
    @XML2.value('(/NewDataSet/Employee/Salary)[1]', 'varchar(25)') AS 'Salary'
)
SELECT
    'Old values', od.*
FROM OldData od
UNION
SELECT 'New values', nd.*
FROM NewData nd

Gives you an output of:

            EmpID  Name   DOB                       DeptID   Salary
Old values  1005   keith  1981-12-02 00:00:00.000   ACC001   10,500
New values  1006   keith  1981-05-02 00:00:00.000   ACC002   10,900

SQL Server is great for storing and manipulating data - but presentation like this should be done in a front-end application (like an ASP.NET application) - not in T-SQL....