| Bug #46290 | SELECT COUNT(*) FROM ... does'nt work with libmysql client library | ||
|---|---|---|---|
| Submitted: | 18 Jul 2009 22:24 | Modified: | 10 Feb 2018 17:44 |
| Reporter: | Roberto Farioli | Email Updates: | |
| Status: | Can't repeat | Impact on me: | |
| Category: | MySQL Server: DML | Severity: | S2 (Serious) |
| Version: | MySQL 5.1.34 comunitiy edition | OS: | Windows |
| Assigned to: | CPU Architecture: | Any | |
| Tags: | count(*), libmysql | ||
[19 Jul 2009 7:05]
Valeriy Kravchuk
Thank you for the problem report. Please, send the results of: select coun(*) from tablename; show create table tablename\G show table status like 'tablename'\G from mysql command line client. Send also the result you get in your application using OleDB.
[19 Jul 2009 13:42]
Roberto Farioli
SELECT COUNT(*) FROM `test`.`datalogger` Returns 5310 show create table `test`.`datalogger` Returns "Table","Create Table datalogger" "CREATE TABLE `datalogger` ( `DataOra` datetime NOT NULL, `increment.R4` double DEFAULT '0', `increment.R8` double DEFAULT '0', `increment.UI1` double DEFAULT '0', `increment.UI2` double DEFAULT '0', `increment.UI4` double DEFAULT '0', PRIMARY KEY (`DataOra`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1" show table status Returns "Name","Engine","Version","Row_format","Rows","Avg_row_length","Data_length","Max_data_length","Index_length","Data_free","Auto_increment","Create_time","Update_time","Check_time","Collation","Checksum","Create_options","Comment" "datalogger","InnoDB",10,"Compact",5626,75,425984,0,0,8388608,,"2009-07-19 00:44:16","","","latin1_swedish_ci",,"","" "datalogger1","InnoDB",10,"Compact",5272,80,425984,0,0,8388608,,"2009-07-19 00:44:17","","","latin1_swedish_ci",,"","" "datalogger2","InnoDB",10,"Compact",5088,83,425984,0,0,8388608,,"2009-07-19 00:44:17","","","latin1_swedish_ci",,"","" "datalogger3","InnoDB",10,"Compact",5626,75,425984,0,0,8388608,,"2009-07-19 00:44:18","","","latin1_swedish_ci",,"","" "datalogger4","InnoDB",10,"Compact",5272,80,425984,0,0,8388608,,"2009-07-19 00:44:18","","","latin1_swedish_ci",,"","" "datalogger5","InnoDB",10,"Compact",5091,83,425984,0,0,8388608,,"2009-07-19 00:44:19","","","latin1_swedish_ci",,"","" "datalogger6","InnoDB",10,"Compact",5626,75,425984,0,0,8388608,,"2009-07-19 00:44:19","","","latin1_swedish_ci",,"","" "datalogger7","InnoDB",10,"Compact",5272,80,425984,0,0,8388608,,"2009-07-19 00:44:20","","","latin1_swedish_ci",,"","" "datalogger8","InnoDB",10,"Compact",5094,83,425984,0,0,8388608,,"2009-07-19 00:44:20","","","latin1_swedish_ci",,"","" "datalogger9","InnoDB",10,"Compact",5626,75,425984,0,0,8388608,,"2009-07-19 00:44:21","","","latin1_swedish_ci",,"","" My variable pBind [0].dblDate is not update with the Count(*) result, others DB work fine with same code.
[19 Jul 2009 15:12]
Valeriy Kravchuk
In your code I see this:
CString csSqlSelect(_T("SELECT COUNT(*) FROM TableName"));
Now, what is TableName in the above? It is your function's parameter? How do you pass real table name there? I also see this:
HRESULT hr = rs.Open (*pSession, csSqlSelect);
if (hr == S_OK)
{
...
So, your variable will not be updated if hs is not equal to S_OK, that is, in case of any error. Maybe you should print out hr value and/or check for possible error to find the real reason of the problem...
[19 Jul 2009 15:38]
Roberto Farioli
My code for 'DataLogger' table is
CString csSqlSelect(_T("SELECT COUNT(*) FROM Datalogger"));
HRESULT hr = rs.Open (*pSession, csSqlSelect);
if (hr == S_OK)
{
Command is opened OK, so hr is S_OK,
if (pRS->MoveFirst () == S_OK)
Rowset MoveFirst is S_OK
I searched in libmysql sources (debugged with my project) and I think there is an error in what libmysql send to Mysql Service (TCp/IP) when the request is COUNT(*)
[20 Jul 2009 7:04]
Tonci Grgin
Hi Roberto. I truly don't know what "MySql OleDB Provider 3.9.6." and I doubt we made it... As for return result of *any* function in MySQL, it is output as sequence of bytes (binary) and I guess that's where your code breaks. Please try reading the result with "GetBytes" or some similar function at your disposal and inform us of result.
[20 Aug 2009 23:00]
Bugs System
No feedback was provided for this bug for over a month, so it is being suspended automatically. If you are able to provide the information that was originally requested, please do so and change the status of the bug back to "Open".
[10 Feb 2018 17:44]
Roy Lyseng
Posted by developer: Closing since it has been suspended for more than 8 years.
Description: I have a Windows C++ program using libmysql.dll with libmysql.lib importing library. When I run this query "SELECT COUNT(*) FROM 'table'", the return isn't the correct rows number. I'm using MySql OleDB Provider 3.9.6. How to repeat: long lCount = 0; CString csSqlSelect(_T("SELECT COUNT(*) FROM TableName")); CCommand<CManualAccessor> rs; MYBIND * pBind = NULL; pBind = new MYBIND [1]; rs.CreateAccessor (1, pBind, sizeof (MYBIND)); rs.AddBindEntry (1, DBTYPE_R8, sizeof (double), &pBind [0].dblDate, NULL, &pBind [0].dwStatus); HRESULT hr = rs.Open (*pSession, csSqlSelect); if (hr == S_OK) { CRowset * pRS = (CRowset *) &rs; if (pRS->MoveFirst () == S_OK) { if (pBind [0].dwStatus == DBSTATUS_S_ISNULL) pBind [0].dblDate = 0; lCount = pBind [0].dblDate; } } delete [] pBind; return lCount;