Question

I have a query to insert a row into a table, which has a field called ID, which is populated using an AUTO_INCREMENT on the column. I need to get this value for the next bit of functionality, but when I run the following, it always returns 0 even though the actual value is not 0:

MySqlCommand comm = connect.CreateCommand(); comm.CommandText = insertInvoice; comm.CommandText += '\'' + invoiceDate.ToString('yyyy:MM:dd hh:mm:ss') + '\', ' + bookFee + ', ' + adminFee + ', ' + totalFee + ', ' + customerID +  ')'; int id = Convert.ToInt32(comm.ExecuteScalar()); 

According to my understanding, this should return the ID column, but it just returns 0 every time. Any ideas?

EDIT:

When I run:

'INSERT INTO INVOICE (INVOICE_DATE, BOOK_FEE, ADMIN_FEE, TOTAL_FEE, CUSTOMER_ID) VALUES ('2009:01:01 10:21:12', 50, 7, 57, 2134);last_insert_id();' 

I get:

{'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'last_insert_id()' at line 1'} 

Answer 1

[Edit: added ‘select’ before references to last_insert_id()]

What about running ‘select last_insert_id();‘ after your insert?

MySqlCommand comm = connect.CreateCommand(); comm.CommandText = insertInvoice; comm.CommandText += '\'' + invoiceDate.ToString('yyyy:MM:dd hh:mm:ss') + '\', '       + bookFee + ', ' + adminFee + ', ' + totalFee + ', ' + customerID +  ');';     + 'select last_insert_id();'  int id = Convert.ToInt32(comm.ExecuteScalar()); 

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Edit: As duffymo mentioned, you really would be well served using parameterized queries like this.

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Edit: Until you switch over to a parameterized version, you might find peace with string.Format:

comm.CommandText = string.Format('{0} '{1}', {2}, {3}, {4}, {5}); select last_insert_id();',   insertInvoice, invoiceDate.ToString(...), bookFee, adminFee, totalFee, customerID);