LIKE query on an Access database via C# always returns COUNT(*) of 0
-
21-12-2019 - |
Question
Please look into following code:
using (OleDbConnection openCon = new OleDbConnection(ConfigurationManager.AppSettings["AccessConnectioString"]))
{
openCon.Open();
string tc = string.Empty;
string ttc = string.Empty;
if (!string.IsNullOrEmpty(QSetId))
{
tc = "select count(*) as [Count] from ABC where QSetId = @qSetId and TText like 'RT*'";
}
else
{
tc = "select count(*) as [Count] from PQR where TText like 'RT*'";
}
using (OleDbCommand qtc= new OleDbCommand(tc))
{
qtc.Connection = openCon;
if (!string.IsNullOrEmpty(QSetId))
qtc.Parameters.Add("@qSetId", OleDbType.VarChar).Value = QSetId;
OleDbDataReader dr1 = qtc.ExecuteReader();
while (dr1.Read())
{
ttCnt = (int)dr1["Count"];
}
}
openCon.Close();
}
I am always getting count as 0 instead of some integer value. While debugging I take the query and execute in MS ACCESS 2013, it gives me correct result. I am not getting what is the issue.
Solution
You are getting tripped up by the difference in LIKE wildcard characters between queries run in Access itself and queries run from an external application.
When running a query from within Access itself you need to use the asterisk as the wildcard character: LIKE 'RT*'
.
When running a query from an external application (like your C# app) you need to use the percent sign as the wildcard character: LIKE 'RT%'
.
OTHER TIPS
Try ExecuteScalar()
method
Replace This:
OleDbDataReader dr1 = qtc.ExecuteReader();
while (dr1.Read())
{
ttCnt = (int)dr1["Count"];
}
With This:
ttCnt = Convert.ToInt32(qtc.ExecuteScalar());
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