How do I re-define the SQL in a QueryDef? I have code that works by deleting and re-creating the QueryDef, but I can't get the overwrite to work - mysql

Question

I am told (and agree) that it is better to replace the SQL in an existing querydef, rather than delete and re-define the querydef each time the query needs to change. But my code only seems to work the second way. Here is the code I have that works:
Dim db As Database
Set db = CurrentDb
Dim QD As QueryDef
Dim mySql As String
mySql = ""
mySql = "TRANSFORM COUNT(tblDocs.Document) AS CountOfDocument " & _
"SELECT tblDocs.[Contractor Dept], " & _
"COUNT(tblDocs.Document) AS [Total Of Document] " & _
"FROM tblDocs " & _
"GROUP BY tblDocs.[Contractor Dept] " & _
"PIVOT tblDocs.[Engineering Status Code]"
On Error Resume Next
db.QueryDefs.Delete "qryX" 'Remove temporary query if exists
Set QD = db.CreateQueryDef("qryX", mySql) 'create temporary query
DoCmd.RunSQL "SELECT * INTO tblDocsCrossTabX FROM qryX;"
Here is the code I can't get to work
Dim db As Database
Set db = CurrentDb
Dim QD As QueryDef
Dim mySql As String
mySql = " "
Set QD = db.CreateQueryDef(("qryX"), mySql)
mySql = "TRANSFORM COUNT(tblDocs.Document) AS CountOfDocument " & _
"SELECT tblDocs.[Contractor Dept], " & _
"COUNT(tblDocs.Document) AS [Total Of Document] " & _
"FROM tblDocs " & _
"GROUP BY tblDocs.[Contractor Dept] " & _
"PIVOT tblDocs.[Engineering Status Code]"
QD.SQL = mySQL 'overwrite query SQL
DoCmd.RunSQL "SELECT * INTO tblDocsCrossTabX FROM qryX;"
Oddly, the second version doesn't throw any errors at me, but it doesn't make the crosstab table at all.
Edit: Maybe I wasn't clear enough. The problem is that the second set of code Does. Not. Execute. The. SQL. If it executed the code, I would be happy to re-write and use the same temp query over and over, but it does. not. execute. the. SQL..
Please respond with how to make the code in the second block actually execute the indicated SQL statement and build the desired table.
I know I have to remake a query if I delete it. Duh.
I know I "should" be able to re-use the same query if I can get the Set statement to properly overwrite the previous sql with the desired sql.
I know you all want to provide an answer, but please make it an answer to the question I am asking.

Answer 1

You can recycle the object if you don't delete it:
' On Error Resume Next
Set QD = db.QueryDefs("qryX")
QD.SQL = mySQL
DoCmd.RunSQL "SELECT * INTO tblDocsCrossTabX FROM qryX;"

Answer 2

Solved.
In the first block of code, when I delete and recreate the query, the string mySql contains a valid SQL statement, so Access is able to assign that SQL to the querydef when I completely recreate it with SET. Specifically,
mySql = "Transform..."
Comes Before
Set QD = db.CreateQueryDef("qryX", mySql)
In the second set of code, the string mySql contains only a space when the Set command is used, as " " is not a valid SQL Statement, the Set command won't even get executed, and the QueryDef QD never even gets created.
Specifically, the error in the second code occurs because
mySql = " " 'NOT a valid SQL Statement
comes before the attempt to create the queryDef
Set QD = db.CreateQueryDef(("qryX"), mySql) 'QD never gets created because mySql is not valid SQL
preventing the assignment of a valid SQL statement later, and so no table gets created.

Answer 3

If you can use a subquery, you can use a tempory QueryDef instead of bothering with checking forQueryDefalready existing or not, just combine the SELECT and the INSERT-Query to use a temporaryQueryDef
Unfortunally you can't useTransformin a subquery so this code leads toRuntime-Error 3129 Invalid SQL statement.
Sql = "SELECT * INTO tblDocsCrossTabX FROM (TRANSFORM COUNT(tblDocs.Document) AS CountOfDocument " & _
"SELECT tblDocs.[Contractor Dept], " & _
"COUNT(tblDocs.Document) AS [Total Of Document] " & _
"FROM tblDocs " & _
"GROUP BY tblDocs.[Contractor Dept] " & _
"PIVOT tblDocs.[Engineering Status Code])"
With CurrentDb.CreateQueryDef(vbNullString) 'or db.CreateQueryDef("") creates a not named and therefore temporary QueryDef
.SQL = Sql
.Execute dbFailOnError
End With

Answer 4

Sample of successful code.
Dim db As Database
Set db = CurrentDb
Dim QueryString As String
Dim QDDocsCross As QueryDef
Set QDDocsCross = db.CreateQueryDef("DocsCross")
QueryString = "TRANSFORM COUNT(Docs.Document) AS CountOfDocument " & _
"SELECT Docs.[Contractor Dept], " & _
"COUNT(Docs.Document) AS [Total Of Document] " & _
"FROM Docs " & _
"GROUP BY Docs.[Contractor Dept] " & _
"PIVOT Docs.[Engineering Status Code]"
QDDocsCross.SQL = QueryString