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Querying CSV file through VBA without knowing the header

Posted on 2013-06-04
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Last Modified: 2013-06-04
Hi,

I'm creating a macro that queries a CSV file that a user chooses, and saves the result of only the lines that meet a certain criteria.

The CSV file contains 7 columns, but 2 of which the headers are dates so they vary.  I need a way to be able to either find out the header names before running the query, or specify in the query through a header number.

e.g.
My file contains the following CSV file:
Curr,Days,1/1/2013,1/2/2013,Change,%Change
USD,1,100,100,0,0
JPY,1,1000,1000,0,0
....

Below is my code
objConn = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
        "Data Source=" & dSource & ";" & _
        "Extended Properties=""text;HDR=Yes;FMT=Delimited(,)"";Persist Security Info=False"
objConn.Open



SqlQry = "SELECT * FROM " & dfile & " " & _
            "WHERE ([% Change] >= 5 OR [% Change] <= -5) "

Rcdset.Open SqlQry, objConn

For i = 0 To Rcdset.Fields.Count - 1
    data_ws.Cells(1, i + 1).Value = Rcdset.Fields(i).Name
Next i

data_ws.Cells(2, 1).CopyFromRecordset Rcdset

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So basically I'm looking for anything that has a 5% change, and I also need to look for any that didn't have data on today's column.  So in this case, it would be WHERE 1/2/2013 = '' but how can I chose this column/header when the value is constantly going to change?
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Question by:iamnamja
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4 Comments
 
LVL 85

Expert Comment

by:Rory Archibald
ID: 39219160
Are the fields always in the same order? If so, perhaps specify HDR=No in the connection and use F4 for today's field and F6 for the % change field. Then you just need to skip the first record in your processing.
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LVL 35

Accepted Solution

by:
[ fanpages ] earned 500 total points
ID: 39219178
Hi,

If you change the "HDR=Yes" part of the connection string to "HDR=No" you should be able to refer to the columns of data in your SQL SELECT statement as follows:

SELECT [F1], [F2], [F3], [F4],.... [F"N"] {where "N" is how many columns are present within the file}
FROM {filename}

(i.e. use the "SELECT [F{column number}]" syntax instead of "SELECT *")

However, if you wish to know the names of the headings to the columns you should either open the file once to retrieve the first few rows & write code to then extract the heading titles you require before re-querying the file contents (for a second time) with named headings...

...or import the first two records only (SELECT TOP 2 * FROM...) still with the "HDR=No" attribute within the connection string.  You can then review the resultset to gain the column headings.

BFN,

fp.
0
 

Author Closing Comment

by:iamnamja
ID: 39219189
Thanks while waiting, I did just this... I queried it twice. Once to get the header, and once to use the header to query it.  Thanks!
0
 
LVL 35

Expert Comment

by:[ fanpages ]
ID: 39219257
Sorry I took seven minutes to reply! ;)
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