I have a query written that will return a single record (a class number) from table1. This class number is the title of a column that I want to select in another table (table2). I want to use this subquery as a mechanism to select this column. Can this be done?
I know this may be bad design but I am just wondering if this sort of thing is possible in MS Access SQL. I know it is not as powerful as MySQL.
The only way you're ever going to do this is using VBA to write the SQL, which really isn't a bad thing. I'd do it sort of like this:
Dim db as Database
Dim rec as Recordset
Dim MyVar = String '(or whatever the datatype is for ClassNumber in Table1)
Dim sSQL as String
Dim qdfNew As DAO.QueryDef
Dim qryLoop As QueryDef
Set db = CurrentDB
Set rec = db.OpenRecordset("SELECT ClassNumber from Table1")
MyVar = rec(0)
'First check to see if the query already exists. If so, delete it.
For Each qryLoop In CurrentDb.QueryDefs
If qryLoop.Name = MyVar Then
DoCmd.DeleteObject acQuery, MyVar
End If
Next
'This will select only the field that relates to the ClassNumber above
sSQL = "SELECT " & MyVar & " FROM Table2"
Set qdfNew = db.CreateQueryDef("MyNewQuery", sSQL)
Then, MyNewQuery is a permanent query in your database which can be used in other queries.
There might be a better option, but I can only think of:
Heinous case statement to choose the right column.
Using VBA.
Correcting the table design, turning the field name into a value
that can be joined upon.
Related
I am with a little bit of a coding problem that I don't know how to solve. I want to put in the table as a record a field name of another table in the same Database.
I will give you an example:
Table1
What I have
Table 2
What I want
The table 1 is update weekly from an external source so I need to record the field name as a record in the second table using VBA language. Does anybody knows if it's possible?
Thank You in advance
You could do something like this
Dim db As Database
Dim fld As Field
Dim sql As String
Set db = CurrentDb
For Each fld In db.TableDefs("YourTable").Fields
sql = "Insert into YourSummaryTable([Date], Hours) select '" & fld.Name & "', sum([" & fld.Name & "]) as s from YourTable"
DoCmd.RunSQL sql
Next fld
Note that you've used a reserved word Date as a fieldname, which isn't best practice and requires the use of the square brackets in the query.
I have searched for a question that I am having, though I find parts of the answer I am not able to understand it fully. I am using access2010.
In simple Terms, I want to filter a table [newsearch] to show the results based on my WHERE condition.
I can use SELECT and a WHERE condition and I get a result through a query, but I want this result to be saved into [newsearch], that means I want this [newsearch] to contain only the results of this query.
I tried using SELECT INTO but since my source and destination are [newsearch], it does not work.
the query I run now is:
strSQL = "SELECT * FROM [newsearch] WHERE [newsearch].[" & Me.Combo17 & "] = '" & Me.Text18 & "'"
Set qdef = db.CreateQueryDef("User query results", strSQL)
qdef.close
Set qdef = Nothing
Set db = Nothing
DoCmd.OpenQuery "User query results", acViewNormal
This gives me the result in a query table but I want it saved to [newsearch].
How can I do it?
select into query creates a table, but obviously you cannot create a table that already exists. You have 2 options:
Instead of selecting what you need, delete those records from your table that you do not need: delete from [newsearch] where field3<>xyz
You can use select into to create a new table, then drop [newsearch] and then rename the new table to [newsearch].
Is there a way to be prompted before you a run an SQL query in Access, to enter in the table name that you wish to query? For example, lets say the columns will always stay constant. The columns could be called "Fruit" and "Date." But, the table name could change depending on the batch number. Ie. table name could be "BatchNO_1" or "BatchNO_2" or "BatchNO_3" etc. So Lets say i have an SQL like:
select Fruit, Date from BatchNO_1 where Fruit = "Apples"
Is there a way that I can be prompted to enter in the table name and have the SQL use the table name i enter to perform the query?
No. The table name cannot be passed as parameter to a query. You will have to construct the query yourself.
Dim tableName as String, sql As String
tableName = InputBox("Please enter the table name")
If tableName <> "" Then
sql = "SELECT Fruit, Date FROM [" & tableName & "] WHERE Fruit = 'Apples'"
'TODO: execute the query here
End If
For instance, you could change the query text of an existing query like this:
CurrentDb.QueryDefs("myQuery").SQL = sql
Or you could execute the query like this
Dim db As DAO.Database, rs As DAO.Recordset
Set db = CurrentDb
Set rs = db.OpenRecordset(sql)
Do Until rs.EOF
Debug.Print rs!Fruit & " " & rs!Date
rs.MoveNext
Loop
rs.Close: Set rs = Nothing
db.Close: set db = Nothing
By putting the batch number in the table name instead of as a column, you are encoding data in the schema. This is not best practice, so in my opinion, the correct answer is to change your database design.
Make a single Batch table with all the columns from your current BatchNo tables, but add a column named BatchNo as part of the primary key. Load all the data from your BatchNo tables into this one, and then delete those tables. Then your query will straightforwardly look like this:
SELECT Fruit, Date
FROM Batch
WHERE
Fruit = "Apples"
AND BatchNo = [Enter Batch No];
Don't put data in table names. That is not the way databases are supposed to be made.
Just to explain a little bit, the reason that your current design violates best practice is due to exactly the problem you are facing now--the shenanigans and weird things you have to do to work with such a design and try to perform operations in a reasonable, data-driven, way.
By having the user enter the table name, you also create the danger of SQL injection if you aren't also careful to compare the user-provided table name to a whitelist of allowed table names. While this may not be such a big deal in Access, it is still heading down the wrong path and is training for something else besides professional database work. If you would ever like to grow your career, it would be regrettable to first have to unlearn a bunch of stuff before you could even start with a "clean slate" to learn the right way to do things.
I would like to use a query to loop through tables that are similar in structure but have different names (ie. tableJan2011, tableFeb2011, tableMar2011 etc.)
Is there a way in MS Access and in SQL Server to use the same query statement while varying the table name within it. (similar to using parameter values) (need this to add different input to each different month's table)
This is a bad table design. You should have a singe table, where you have a column(s) to indicate month/year. You would then just query this single table and add a WHERE month='X' and YEAR='Y' to limit your results to what you need.
without a table redesign use UNION and clever WHERE clause parameters, which will cause rows to only come from the table that applies.
SELECT
..
FROM tableJan2011
where...
UNION
SELECT
..
FROM tableFeb2011
where...
UNION
SELECT
..
FROM tableMar2011
where...
First off, listen to the people who are telling you to use one table. They know of which they speak.
If you can't do that for some obscure reason (such as inheriting the design & not being allowed to change it), then you're stuck writing VBA code. There's no way that I know of, in Access, to substitute source tables (or even source columns--values only), in a saved QueryDef.
You'll need something like this:
Private Function QueryTable (strTableName as String) As DAO.Recordset
Const theQuery as String = "SELECT tbl.* FROM [table] As tbl"
Dim sSql As String
Dim db As DAO.Database
Dim rs As DAO.Recordset
sSql = Replace(theQuery, "[table]", strTableName)
Set db = CurrentDb()
Set rs = db.OpenRecordset(sSql)
Set QueryTable = rs
End Function
Note that this is simplified code. There's no error handling, I haven't released the objects (which I usually do, even though they'll go out of scope), and SELECT * is almost always a bad idea.
You'd then call this function wherever you need it, passing in the name of the table.
consider moving the year and month out of the table name and into columns in one table.
you can create a table with query or table names to use at runtime, but you have to be able to write Access BASIC code in a module.
Here's an example, assuming you have a query built on a table with the query names you want to execute:
Set db = CurrentDb
Set rsPTAppend = db.OpenRecordset("qry_PTAppend")
rsPTAppend.MoveFirst
Do Until rsPTAppend.EOF
qryPT = rsPTAppend("PT")
Set qdef = db.QueryDefs(qryPT)
sqlOld = qdef.sql
sqlNew = sqlOld
' manipulate sql
If sqlNew <> sqlOld Then
qdef.sql = sqlNew
End If
db.QueryDefs(rsPTAppend("append")).Execute
If sqlNew <> sqlOld Then
qdef.sql = sqlOld
End If
rsPTAppend.MoveNext
Loop
Don't know what is possible in Access but in SQL Server you could create a view that use union to get all tables together and then build your queries against the view.
One other option you have could be to build your queries dynamically.
In sql server you can execute a string as sql.
http://msdn.microsoft.com/en-us/library/ms175170.aspx
I'm not aware of anything similar in MS Access (though my experience is limited). You could however dynamically generate your sql in code to accomplish this. Perhaps you could create a function to take the table suffix and parameters and build the desired sql that way.
select * from *
yes this is what I want I want to return all fields from all table in my ACCESS database regardless the fields names or the tables names!!!
for example if I have table1 and table2 as tables in my database access file
what I want is to generate this statement
select * from table1,table2
from sql query which run fine in access query
but again I don't know the name of the tables which in the access file.
is there a way for that?
This query will list all the table names
SELECT MSysObjects.Name
FROM MSysObjects
WHERE (((MSysObjects.Type)=6))
You can also use this bit of code to go through every table and list every field
Public Sub List_fields_in_tables()
Dim tdf As DAO.TableDef
Dim fld As DAO.Field
For Each tdf In CurrentDb.TableDefs
For Each fld In tdf.Fields
Debug.Print "Table='" & tdf.name & "' Field='" & fld.name & "'"
Next fld
Next tdf
End Sub
Hope this helps
To achieve this you should use from Master database in SQL Server
Master database contains information about all columns of all of your databases. also there is catalog view to gain information about an exact database.
Just use Master stored procedures