Select from hundreds of tables at once (.mdb) - sql

Question

We have .mdb file with hundreds of tables: Lesson1, Lesson2, Lesson3, Lesson4, etc. All tables have the same structure:
Lesson<n>
----------------
slide_id
name
description
status
created_date
created_by
updated_date
updated_by
What SQL statement would generate a result like this:
| table_name | slide_id | name |
|-----------------------|-------------------------------|
| Lesson1 | 1 | name for slide 1 of lesson 1 |
| Lesson1 | 2 | name for slide 2 of lesson 1 |
| Lesson2 | 1 | name for slide 1 of lesson 2 |
| Lesson2 | 2 | whatever |
| Lesson2 | 3 | again whatever |
etc.
So there are a few points here:
table names must be included
there are hundreds of tables

Answer 1

If the table names are known, you can create a query like:
SELECT 'Lesson1' AS table_name, slide_id, name, ... FROM Lesson1
UNION ALL SELECT 'Lesson2', slide_id, name, ... FROM Lesson2
UNION ALL SELECT 'Lesson3', slide_id, name, ... FROM Lesson3
UNION ALL SELECT 'Lesson4', slide_id, name, ... FROM Lesson4
UNION ALL SELECT 'Lesson5', slide_id, name, ... FROM Lesson5
Cursors are only needed if the number of tables is in constant flux. If not, this should do the trick.
Hint: to generate the initial query, paste the names of the table in Excel, and use a formula in the next cell over to create that table's "UNION ALL" statement. Then copy and paste straight back into Access. (Or create it dynamically using a cursor, but copy/paste and a quick formula is easy, and you can save the excel file just in case you need to add tables in bulk, change the columns selected, etc.)
And, obviously, the end solution should be to consolidate the tables, if possible, and add a discriminator field when querying. Heck, if you have to, it's easier to maintain hundreds of queries that each pull one lesson's rows (again, Excel can be a handy batch-update tool), than hundreds of lessons tables that must have identical structures.

Answer 2

Using sql server, I can unfortunately see this only done with a CURSOR X-(.
This should help
DECLARE #Name VARCHAR(50)
DECLARE Cur CURSOR FOR
SELECT name
FROM sysobjects
WHERE xtype = 'U'
and name like 'Lesson%'
OPEN Cur
FETCH NEXT FROM Cur INTO #Name
DECLARE #RetTable TABLE(
TableName VARCHAR(50),
slide_id INT,
name VARCHAR(100)
)
WHILE ##FETCH_STATUS = 0
BEGIN
INSERT INTO #RetTable EXEC ('SELECT ''' + #Name + ''',slide_id , Name FROM ' + #Name)
FETCH NEXT FROM Cur INTO #Name
END
CLOSE Cur
DEALLOCATE Cur
SELECT *
FROm #RetTable
OK, then if you can use a macro/vba code you can create a temp table called AllLessons and run the following code. I tested this from a form with a button.
Private Sub Command0_Click()
Dim iTable As Integer
For iTable = 0 To CurrentDb.TableDefs.Count - 1
Dim tableName As String
tableName = CurrentDb.TableDefs(iTable).Name
If (Left(tableName, Len("Lesson")) = "Lesson") Then
CurrentDb.Execute "INSERT INTO AllLessons ([table_name],[slide_id],[name]) SELECT """ & tableName & """, [slide_id],[name] FROM " & tableName
End If
Next iTable
End Sub