How to perform an update query from a UDF that receives parameters from multiple tables?

bfuchs
bfuchs used Ask the Experts™
on
Hi Experts,

I have a table called Employeestbl

I would like to perform an update to a field of this table to all records that a UDF called EmployeesMissingDocs returns '1'.

Now my main issue is that this UDF expects values as parameters from different tables.

See example below

FUNCTION [dbo].[EmployeesMissingDocs] (
@EmployeeID int,
@Title varchar(50) = null,
@LicenseNumSignedYN bit = null,
@LicenseExpires DATETIME= null,
@BclsExpires DATETIME= null 
) RETURNS VARCHAR(2000)

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Where EmployeeID and Title come from Employeestbl, License info come from a second table and Bcls from a third one..

How can I perform this in a single update statement?
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Commented:
Use a CTE, contruct a query that uses the neede tables and returns the wanted rows. Then update the tsble using that CTE.
SharathData Engineer
Commented:
You can try CROSS APPLY. Replace <join condition> with your actual JOIN condition between tables.

SELECT *
  FROM Employeestbl e
  JOIN License l ON <join condition>
  JOIN third_table a ON <join condition>
 CROSS APPLY (SELECT dbo.EmployeesMissingDocs(e.EmployeeID, e.Title, l.LicenseNumSignedYN, l.LicenseExpires, a.BclsExpires) AS ReturnValue) t1

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 UPDATE e
    SET your_column = t1.ReturnValue
   FROM Employeestbl e
  JOIN License l ON <join condition>
  JOIN third_table a ON <join condition>
 CROSS APPLY (SELECT dbo.EmployeesMissingDocs(e.EmployeeID, e.Title, l.LicenseNumSignedYN, l.LicenseExpires, a.BclsExpires) AS ReturnValue) t1

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The UDF really doesn't care where the parameters come from.  It's up to the calling operation to pass the correct parameter(s).

Can you clarify what you're trying to do?
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Hi Experts,

First thanks for replying..

Perhaps you can help me apply your suggestions given the details below:

A- the table/field I'm looking to update is EmployeesJcahoInfo.EmployeeID

(So in other words the SQL statement should be something like "Update EmployeesJcahoInfo.EmployeeID set MyField = False where EmployeesMissingDocs (Param1,Param2,Param3..) = '1')

B- the query joins needed for the UDF parameters are as follows

           
dbo.CoreMandatory RIGHT OUTER JOIN
                         dbo.Employeestbl ON dbo.CoreMandatory.EmployeeID = dbo.Employeestbl.ID LEFT OUTER JOIN
                         dbo.Facilitiestbl LEFT OUTER JOIN
                         dbo.FacilitiesDocumentsRequirements ON dbo.Facilitiestbl.ID = dbo.FacilitiesDocumentsRequirements.FacilityID RIGHT OUTER JOIN
                         dbo.TovInfo ON dbo.Facilitiestbl.Tov_ID1 = dbo.TovInfo.TovCode ON dbo.Employeestbl.ID = dbo.TovInfo.EmployeeID 

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C- the list of parameters is quite long (I just listed in OQ the first few), I guess you dont need them, will figure this out already once I have an example.

D- let me know if you need more info.

Thanks,
Ben
@KDO,
The UDF really doesn't care where the parameters come from.
Well if they would all come from one table (let say EmployeesJcahoInfo), I would have no problem executing it like this
Update EmployeesJcahoInfo.EmployeeID set MyField = False where EmployeesMissingDocs (EmployeesJcahoInfo.Field1,EmployeesJcahoInfo.Field2,EmployeesJcahoInfo.Field3..) = '1')

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The whole issue is how to get those parameters supplied, and if I try to do this on a joined sql results then it becomes non updatable.

Thanks,
Ben
Hi Ben,

It may be best to write the update statement without relying on the UDF.  It may not code to be the shortest, but it will likely be the fastest and least complicated.

SQL Server allows you to join tables in an UPDATE statement like this:

UPDATE
    mytable
SET
    col1 = value1,
    col2 = value2 ...
FROM
    TableA A
    JOIN
    TableB B
      ON A.colx = B.colxy
  WHERE
    condition(s)

Based on what I've seen in this thread you should be able to fit your requirements (parameters) into this structure.


Kent
@Kdo,
write the update statement without relying on the UDF......WHERE
    condition(s)
Not sure what you mean by that, as the where condition is the point I need to use the UDF for?
SQL Server allows you to join tables in an UPDATE statement
Are you saying I can have all those outer joins shown above (ID: 41738208) embedded in this update statement?
Thanks,
Ben
SharathData Engineer

Commented:
Did you look into my post?
>> Are you saying I can have all those outer joins shown above (ID: 41738208) embedded in this update statement?

Sure.  All modern database engines support SQL that allows you to join values in a sub-query, though vendors generally don't agree on the correct form so the statements don't always work across platforms without some changes.

Sharath posted an example earlier, too.

Kent
@Sharath, @Kdo,

Testing it, will let you know..

Thanks,
Ben
Worked, thank you guys!

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