"LIKE" operator works in MS Access, but not ADO

Question

I'm trying to filter records using "Like" with asterisks, it works when using Access 2010 returning many records. I'm stumped why it returns nothing when used with ADO. The code includes multiple tables and columns so to troubleshoot I made a simple query. Here's the code:

strsql = "SELECT tproducts.Prod_Name FROM tproducts " _
& " WHERE tproducts.Prod_Name Like " & Chr(34) & "SO*" & Chr(34)

Set cn = New ADODB.Connection
cn = connString
cn.Open
Set rs = New ADODB.Recordset
rs.Open strsql, cn, adOpenStatic, adLockOptimistic

' test here
iRecCount = rs.RecordCount
rs.MoveFirst

Recordcount returns -1.

When "Like" is replaced by "equals" it returns correct record so I'm sure it's able to connect to the database, for example:

strsql = "SELECT tproducts.Prod_Name FROM tproducts " _
& " WHERE tproducts.Prod_Name = " & Chr(34) & "SONY Vaio SVD13213CXB" & Chr(34)

Is there a special way to use the Like operator in ADO?

What other ways can I filter to give results same as using "Like"? For example, to find all "SVD" products?

Crosseye

Answer 1

In MS Access, the wildcard is nearly always *, outside of MS Access it is nearly always %, so

str = "SELECT tproducts.Prod_Name FROM tproducts) " _
& " WHERE tproducts.Prod_Name Like ""SO%"""

However, I strongly recommend that you move to parameters to avoid a number of serious problems.

DAO is by far the better choice for ACE / Jet ( rough example Loop table rows in Access, with or without use of Private Const )

Ethno

Yes, I used asterisk wildcard. It used to be connected to a Mysql database and uses %, however, % returns nothing in MS Access. I tested the statements directly onto MS Access. – Crosseye

You are using ADO, so that is %, not * If you are working with ACE / Jet, it is much more efficient to use DAO. – Ethno

The query is just being passed through ADO to the Access engine (JET engine). ADO doesn't parse the query itself. – Prostitution

@Prostitution The point is the same, with ADO, the query must use %, with DAO * is an option. DAO is much faster when using ACE / Jet. – Ethno

I switched to % wildcard but same result, no records were returned. – Crosseye

Why are you using ADO with ACE / Jet? You can get a recordset that is easy to check the count if you use DAO. – Ethno

Yes I'm considering using DAO but might take a few months to migrate, so not an option at this time. – Crosseye

I stand corrected. I wrote a test app in VBScript (basically the same engine as VB6 with some minor changes) and it does require the '%' character. '*' does not work. I apologize. – Prostitution

Hey, @Zippit, I think we both have valid points : adopenstatic.com/faq/recordcounterror.asp – Ethno

Use ALike in MS Access query design window and see what you get back. ALike will allow you to test % for results. – Ethno

Just for giggles, can you try changing your query as follows (note the removal of the CHR(34) calls): str = "SELECT tproducts.Prod_Name FROM tproducts WHERE tproducts.Prod_Name Like 'SO%' " – Prostitution

@Prostitution you may need to watch that for embedded single quotes, yesno? – Ethno

OH, absolutely. This is just a proof of concept to get it working. You still need to harden it against SQL-Injection. Like you said, use parameters. Of course, that would still be an issue with the CHR(34) as well. – Prostitution

Let us continue this discussion in chat. – Prostitution

@Zippit, as you suggested this one worked! strsql = "SELECT tproducts.Prod_Name FROM tproducts " _ & " WHERE tproducts.Prod_Name Like '%SVD%'" – Crosseye

Just a minute, % is my suggestion. Are you saying that you do not have items LIKE 'SO%' ? – Ethno

@Zippit, as you suggested this one worked! strsql = "SELECT tproducts.Prod_Name FROM tproducts " _ & " WHERE tproducts.Prod_Name Like '%SVD%'" It does not return records on Access but works sweet with ADO. So, in conclusion: - don't use chr(34), use single quote instead - use percent % instead of asterisk. Thanks a million! – Crosseye

@ Fionnuala: yes there are over a hundred "Sony" products. Thanks also a million to you for your time and effort to help me out. I'll remember to use % in ADO and * in Access. – Crosseye

You should double the quote characters to include a quote literal or use single quotes where they're supported. – Ordonnance

Searching further I found this info from the book 'SQL for Microsoft Access' by Cecelia L. Allison and Neal A. Berkowitz, page 237: "If your Access database is set to SQL-89 use an asterisk (*) instead of a percent sign (%) in the above SQL script." – Crosseye

Also just found a discussion about this issue: "Microsoft Jet wildcards: asterisk or percentage sign?" – Crosseye

Answer 2

You cannot count on RecordCount. It often returns -1 even if rows were returned. It will only return actual count if you are using a client side cursor.

Instead, use rs.EOF to check for end of recordset. Try something like the following:

Set cn = New ADODB.Connection
cn = connString
cn.Open
Set rs = New ADODB.Recordset
rs.Open strsql, cn, adOpenStatic, adLockOptimistic

' very innefficient way to find the record count, but gives you the idea.  If you just care about record count use "COUNT(*)" in your query
do while not rs.eof
  iRecCount = iRecCount + 1
  rs.MoveNext
loop

Prostitution

But the problem is that "Like" does not always return any record. – Crosseye

How do you know it is not returning any records? As I mentioned above, if you only checking rs.recordCount then you are wrong. You need to check for rs.eof – Prostitution

rs.movenext returns error: Runtime error '3021'. Either BOF or EOF is true, or the current record has been deleted. – Crosseye

Heh...then you're definitely not getting any records back. – Prostitution

So, it seems "Like" does not work on ADO. Is there another way of filtering with wildcards? – Crosseye

Yes it does. See the comments in Fionnuala's answer. I wrote a test app just a few minutes ago using Access and ADO and it works fine. – Prostitution

@Ethno & Zippit, sorry I wish I could but I can't vote at this time. – Crosseye

@SiegfredNeval Do not worry, things sort themselves out. – Ethno

Answer 3

 dim strSQL as string
 dim RC as variant
 dim rs as adodb.recordset
 set rs = new adodb.recordset
 strSQL = "Select * from sometable"

  rs.open strSQL,currentproject.connection, 
  adopenDynamic, adlockOptimistic

  RC = rs.recordcount
  rs.close
  set rs = nothing

is a problem but..

 dim strSQL as string
 dim RC as variant
 dim rs as adodb.recordset
 set rs = new adodb.recordset
 strSQL = "Select * from sometable"

 rs.Open strSQL, CurrentProject.Connection,
 adOpenKeyset, adLockReadOnly

 RC = rs.recordcount
 rs.close
 set rs = nothing

will return the correct record count.

Tabasco