How to write Case Sensitive Query for MS Access?
Solution 1:
You can use the StrComp()
function with vbBinaryCompare
for a case-sensitive comparison. Here is an example from the Immediate window to show how StrComp()
works. See the Access help topic for more details.
? StrComp("a", "A", vbBinaryCompare)
1
? StrComp("a", "A",vbTextCompare)
0
StrComp()
returns 0 if the first two arguments evaluate as equal, 1 or -1 if they are unequal, and Null if either argument is Null.
To use the function in a query, supply the vbBinaryCompare
constant's value (0) rather than its name.
SELECT VCode
FROM VirtualMaster
WHERE StrComp(VirtualMonitorName, "Vm1", 0) = 0;
This approach is also available to queries from other applications if they use the newer Access Database Engine ("ACE") drivers. For example, the following C# code
string myConnectionString =
@"Driver={Microsoft Access Driver (*.mdb, *.accdb)};" +
@"Dbq=C:\Users\Public\Database1.accdb;";
using (OdbcConnection con = new OdbcConnection(myConnectionString))
{
con.Open();
using (var cmd = new OdbcCommand())
{
cmd.Connection = con;
cmd.CommandText =
"SELECT COUNT(*) AS n FROM [VirtualMaster] " +
"WHERE StrComp([VirtualMonitorName],?,?) = 0";
cmd.Parameters.AddWithValue("?", "Vm1");
cmd.Parameters.Add("?", OdbcType.Int);
var vbCompareOptions = new Dictionary<string, int>()
{
{"vbBinaryCompare", 0},
{"vbTextCompare", 1}
};
string currentOption = "";
currentOption = "vbBinaryCompare";
cmd.Parameters[1].Value = vbCompareOptions[currentOption];
Console.WriteLine(
"{0} found {1} record(s)",
currentOption,
Convert.ToInt32(cmd.ExecuteScalar()));
currentOption = "vbTextCompare";
cmd.Parameters[1].Value = vbCompareOptions[currentOption];
Console.WriteLine(
"{0} found {1} record(s)",
currentOption,
Convert.ToInt32(cmd.ExecuteScalar()));
}
}
produces
vbBinaryCompare found 1 record(s)
vbTextCompare found 2 record(s)
Solution 2:
Check this out:
https://support.microsoft.com/kb/244693?wa=wsignin1.0
This article describes four methods of achieving a case-sensitive JOIN using the Microsoft Jet database engine. Each of these methods has advantages and disadvantages that should be weighed before choosing an implementation. The methods are:
- StrComp
- Case-Sensitive IISAM Driver
- Hexadecimal Expansion
- Binary Field
Solution 3:
Using only built-in functions, add an additional custom column in the query design view:
location: InStr(1,[VCode],"VM1",0)
the zero parameter requests binary compare (case sensitive) when finding location of "VM1" within [VCode]
set the criteria in that column to >0
so only records with non-zero location in the vcode matching Like "*vm*"
contain the exact VM1 string -
The WHERE
clause looks like:
WHERE (((VirtualMaster.VCode) Like "\*vm*") AND ((InStr(1,[VCode],"VM1",0))>0));