Question

I have a large number of stored procedures that basically do the same thing: get a list of values as parameters, then go to some table and SELECT all the rows WHERE these values match.

I would like to be able to have a single stored procedure that would be able to handle all these cases.

How would you tackle this?

Answer 1

You can try to use XML based approach for your problem. Send an XML as an input parameter. Convert the xml into a table. From the table form dynamic query and execute it in order to achieve your desired functionality. See the below example. In this example Departments is a table which contains 3 columns pkDepartmentId (int), DepartmentName (varchar) and BuildingNumber (int). Using this approach you can send n Number of parameters and their values as input parameters.

pkDepartmentId DepartmentName BuildingNumber
1 Electronics and Communication 1
2 Computer Science 2
3 Instrumentation and Technology 4

--EXEC TestProc '<Parameters>
--                  <Param>
--                      <ColumnName>pkDepartmentId</ColumnName>
--                      <ColumnValue>1</ColumnValue>        
--                  </Param>
--                  <Param>
--                      <ColumnName>DepartmentName</ColumnName>
--                      <ColumnValue>Electronics and Communication</ColumnValue>        
--                  </Param>
--                  <Param>
--                      <ColumnName>BuildingNumber</ColumnName>
--                      <ColumnValue>1</ColumnValue>        
--                  </Param>    
--              </Parameters>'

CREATE PROCEDURE TestProc
@parameters XML
AS
BEGIN
    DECLARE @temp1 TABLE
    (
          ColName VARCHAR(100)
        , ColVal VARCHAR(4000)      
    )

    INSERT INTO @temp1
    SELECT    Params.Col.value('ColumnName[1]', 'VARCHAR(50)') ColName
            , Params.Col.value('ColumnValue[1]', 'VARCHAR(50)') ColVal              FROM   @parameters.nodes('//Parameters/Param') Params(Col)

    DECLARE @sql VARCHAR(4000)

    SET @sql = 'SELECT * FROM Departments WHERE '

    SELECT @sql = @sql  + ColName + ' = ''' + ColVal  + ''' AND '
    FROM @temp1

    -- Trim last AND
    SET @sql = SUBSTRING(@sql, 1, LEN(@sql) - 3)

    PRINT @sql                  

    EXEC (@sql)             

END

On executing this proc following result is obtained
pkDepartmentId DepartmentName BuildingNumber
1 Electronics and Communication 1