Inner Join of more than one table in C# with SQLite

Question

I need to do an Inner Join with more than one table in my C# program.

I've tried to execute my query using DBeaver in the same database, and it works. But when I use that same query in my C# code, it returns nothing. I know the connection works, since I get data from one of the tables, and that does fill. Also, it did work just doing one inner join. I use the SQLite NuGet Package.

This is my query (the one I used in DBeaver):

SELECT mcc.ModeloId, t.FctrlClusterId, mcc.FctrlClusterDescription, cl.ClusterId, cl.ClusterName, 
t.Command, co.CommandName, t.AttributeId, at.AttributeName, t.DataPosition, t.DataType, t.TramaData
FROM Trama t
INNER JOIN ModeloClusterCanal mcc ON t.FctrlClusterId = mcc.FctrlClusterId 
INNER JOIN Cluster cl ON mcc.ClusterId = cl.ClusterId
INNER JOIN Command co ON t.Command = co.CommandId
INNER JOIN Attribute at ON t.AttributeId = at.AttributeId
WHERE RxTx LIKE 'Tx'

And this is my C# code (with the same query, but using String.Format() ):

private static readonly string tablaCluster = "Cluster";
private static readonly string tablaCommand = "Command";
private static readonly string tablaAttribute = "Attribute";
private static readonly string tablaModeloClusterCanal = "ModeloClusterCanal";
private static readonly string tablaTrama = "Trama";

CommandText = String.Format("SELECT mcc.ModeloId, t.FctrlClusterId, mcc.FctrlClusterDescription, cl.ClusterId, cl.ClusterName, t.Command, " +
    "co.CommandName, t.AttributeId, at.AttributeName, t.DataPosition, t.DataType, t.TramaData " +
    "FROM {0} t " +
    "INNER JOIN {1} mcc ON t.FctrlClusterId = mcc.FctrlClusterId " +
    "INNER JOIN {2} cl ON mcc.ClusterId = cl.ClusterId " +
    "INNER JOIN {3} co ON t.Command = co.CommandId " +
    "INNER JOIN \"{4}\" at ON t.AttributeId = at.AttributeId " +
    "WHERE t.RxTx LIKE 'Tx'", 
    tablaTrama,
    tablaModeloClusterCanal,
    tablaCluster,
    tablaCommand,
    tablaAttribute);

    SqliteAdapter = new SQLiteDataAdapter(CommandText, SqliteConnection);
    SqliteAdapter.Fill(DataSet, "TramasTx");

(before this code, I open the connection and fill the DataSet with another table)

I also tried using the query string directly, without formatting it, but it gave the same result.

In DBeaver, I get the desired columns and the rows I want.

In C#, the Table with which I fill the DataSet has 0 rows.

I tried using parenthesis as said in INNER JOIN to more than one table , but it didn't work either. I really can't see what can cause this.

In case the ER diagram of the DB could help, I can edit the question and add it.

---

I edited the CommandText since I left some parenthesis that shouldn't be there, and I also tried resetting the SqliteCommand variable (because I used it before, with another command), but this didn't work either.我编辑了 CommandText，因为我留下了一些不应该在那里的括号，我还尝试重置 SqliteCommand 变量（因为我之前用过另一个命令），但这也不起作用。 I'm gonna try using another variable for the SQLiteCommand, since I don't know if reusing it could affect the result?

---

I wasn't using at all the SQLiteCommand variable so got rid of it. 我根本没有使用 SQLiteCommand 变量，所以摆脱了它。 I tried disposing of the SQLiteAdapter (since I do use it for the table data I get before), but it didn't work either. It doesn't give me any error or exception, it just creates the Table inside the DataSet, but the row count is 0.

---

I couldn't find the problem with the query. 我找不到查询的问题。 I talked with a colleage and they told me that, since the query works on programs like DBeaver, it might be because the driver in .NET works different. In the end I just collected each table in different DataTables and got the info I needed iterating and using if control statements. I hope this helps someone.

Answer 1

there are 2 issues

1. Why you used inverted quotes in table name ( Attribute ) remove the quotes.
2. In where clause add alias or table name before column name WHERE table.RxTx LIKE 'Tx'"

Hope this will help full for you

Answer 2

It's an old question, and I think I didn't find an appropriate answer, but I'm copy-pasting my last EDIT since it seems that it's the way I resolved my issue.

I couldn't find the problem with the query. I talked with a colleage and they told me that, since the query works on programs like DBeaver, it might be because the driver in .NET works different. In the end I just collected each table in different DataTables and got the info I needed iterating and using if control statements.

I'm marking this as my answer but won't close the post, in case someone finds the real issue at some point.