How to migrate Access queries to SQL views? - sql-server

Question

I am using SQL Server Migration Assistant to create linked tables to link from Access to SQL server. During the migration process I also selected Access queries along with the tables to be migrated. The tables are now migrated and linked. There was no option to link queries automatically. However, out of my 15 queries only 5 of them have migrated. SSMA docs says that:
Most SELECT queries are converted to views. Other queries, such as
UPDATE queries, are not migrated.
SELECT queries that take parameters are not converted, nor are
cross-tab queries.
When converting Access Queries to SQL Views, what would be the best course of action as it is not done automatically? I know that views need to be in T-SQL.

Answer 1

I helped to develop a website that will convert an Access SQL query into T-SQL. Paste in your Access SQL and it will convert and format the result as T-SQL. Test the resulting query in SSMS or an Access pass-through query.
https://accessusergroups.org/sql-converter/
The website applies over 80 conversions to the pasted in query. It can handle a lot of syntax that is specific to Access.
SELECT Instr("Please send feedback & share with friends","e") as Last_E
,DATE() AS Today_Date
,NOW() AS Today_Now
,CDate(DateUpdate) AS DateUpdate_CDate
,CCur([flags]) AS Flags_CCur
,NZ([LV], "LV NULL") AS LV_NZ
,CInt([Type]) AS Type_CInt
,CSng([MsysObjects.DateCreate]) AS DateCreate_CSng
,CDbl([MsysObjects].[DateCreate]) AS DateCreate_CDbl
,TRIM(SPACE(20) & NAME & " ") AS Name_Trim
,LEFT(NAME, 4) AS Name_Left4
,RIGHT(NAME, 4) AS Name_Right4
,MID(NAME, 4,5) AS Name_Mid45
,NOT INSTR(1, NAME, "q") <> 0 AS Name_Contains_q
,IIF(Type = 5, "Query", "Other") AS Type_IIF
,IIF(ISNULL(LvProp), "N/A", LvProp) AS LvProp_Handler
,"Amy's code IS righteous." AS SingleQuotes
,"Al's ""new"" cars" AS DoubleQuotes
,"10 + 10 = "& CStr(10 * 2) AS IgnoreMathSymbols
,DCOUNT("Name","MsysObjects","Name like Q*") as RowCount
FROM MsysObjects
WHERE [NAME] LIKE "*e*"
AND RIGHT(DATE(), 4) = 1010 * 2 + 1
The Access query above will convert to T-SQL as the following. Keep in mind that the MsysObjects table doesn't exist in SQL Server.
SELECT CHARINDEX('e', 'Please send feedback & share with friends' ) as Last_E
,CONVERT(date, GETDATE()) AS Today_Date
,GETDATE() AS Today_Now
,CONVERT(date,DateUpdate) AS DateUpdate_CDate
,CONVERT(money,[flags]) AS Flags_CCur
,ISNULL([LV], 'LV NULL') AS LV_NZ
,CONVERT(int,[Type]) AS Type_CInt
,CONVERT(real,[MsysObjects].[DateCreate]) AS DateCreate_CSng
,CONVERT(real,[MsysObjects].[DateCreate]) AS DateCreate_CDbl
,TRIM(SPACE(20) + NAME + ' ') AS Name_Trim
,LEFT(NAME, 4) AS Name_Left4
,RIGHT(NAME, 4) AS Name_Right4
,SUBSTRING(NAME, 4,5) AS Name_Mid45
,NOT CHARINDEX('q', NAME ,1) <> 0 AS Name_Contains_q
,IIF(Type = 5, 'Query', 'Other') AS Type_IIF
,IIF((LvProp IS NULL) , 'N/A', LvProp) AS LvProp_Handler
,'Amy''s code IS righteous.' AS SingleQuotes
,'Al''s "new" cars' AS DoubleQuotes
,'10 + 10 = '+ CStr(10 * 2) AS IgnoreMathSymbols
,
/* DCOUNT beta conversion */ (
SELECT COUNT(Name)
FROM MsysObjects
WHERE Name LIKE Q%
) as RowCount
FROM MsysObjects
WHERE [NAME] LIKE '%e%'
AND RIGHT(CONVERT(date, GETDATE()) , 4) = 1010 * 2 + 1

Answer 2

As a general rule when migrating to sql server, the select queries on the access client side SHOULD NOT be migrated to sql server. As you noted, ONLY select quires can be migrated, and worse is those views will become read only when linked. (Unless you select a PK during the migration process)
After you migrate the data, and link to those tables, then ALL OF you existing Access queries will continue to work as before.
Those Access saved queries will continue to work as before, and they are now working + using the linked tables. Most access quires do not need to be converted, and they will perform rather well without being converted.
The only exception is those complex queries with say group-by, or complex joins should be converted.
And access client quires in most cases will NOT pull the whole sql server table, so once again, little or no benefit occurs by migrating the access client side queries. I would not migrate them.
So if we have
Select * from tblInvoies where InvoiceNum = 1234
The above does NOT need to be converted to t-sql, nor does it need to be converted to a view. Converting such select quires in access to a sql view will likely introduce bugs and issues into your application.
And as noted, sql server cannot “prompt” you like Access queries can.
You only need or want to covert an access query to a sql view for those queries that are running slow.
I would not migrate ANY access queries to sql server. You are far better off to continue to use the saved Access queries client side. Most of them will not see improved performance by converting to t-sql views.
And you potential introduce a large number of bugs, and issues that will break your application.
Migrate the data tables only. Get the client application working ASAP, and then consider tweaking or migrating some of the access queries that don’t perform well. In a application with say 200 client queries, I find that only 5-10 need to be converted to views.

Answer 3

SQL Server definitely supports Pivots; you'll have to re-crate cross-tabs as Pivots. SQL Server definitely supports parameter queries. Just re-write the SQL. Depending on how complex the queries are, you could perhaps just copy the SQL from Access and paste it into SQL Server. You son't really save queries in SQL Server (although you could export them), but you run queries as Stored Procedures. It takes a bit of getting used to, but once you make the switch away from Access, I'm pretty sure you'll never go back.