Counting records in a QSqLite db

[Venkatesh V]

@gabor53
Hi,
try this query,
SELECT Count(*) FROM TableName;

[gabor53]

@Venkatesh-V
I tried like this:

recCount =  query_fix("SELECT COUNT(*) FROM Items");

and I got the following error message:
C:\Programming\Projects\Folkfriends_bzr\checkout\fixdb.cpp:121: error: no match for call to '(QSqlQuery) (const char [27])'
recCount = query_fix("SELECT COUNT(*) FROM Items");
^
Any idea why?

[SGaist]

Hi,

Because that's not how you use a QSqlQuery object.

A select count should be handled the same as classic select call. You'll just have one result which will contain the number of rows.

[gabor53]

@SGaist
Hi,
Is this supposed to work on QSqLite?

[Venkatesh V]

@gabor53
Hi,

int recCount = query_fix.prepare("SELECT COUNT(*) FROM Items");
query_fix.exec();

[SGaist]

@gabor53 What is supposed to work ?

[gabor53]

@SGaist
select count with QSqLite.

[gabor53]

@Venkatesh-V
This returns 1, but there are 7 records in the db. Any idea why?

 int recNum;
  recNum = query_fix.prepare ("SELECT COUNT(*) FROM Items");
  query_fix.exec ();

  qDebug() << "Record count in fixdb: " << recNum;

[mrjj]

hi
If i show you how the function is defined, can you then guess why its 1 ?
bool QSqlQuery::prepare(const QString & query)

I will give you a hint and say that
query_fix.exec ();
must be used.
Also the value of true is often 1.

[gabor53]

@mrjj
Thank you.Now I understand why it is 1. How can I get around it?

[Venkatesh V]

@gabor53

Hi,
Try this,

int recNum =0;
query_fix.prepare ("SELECT * FROM Items");
if( query_fix.exec ()){
while( query.next() )
{
recNum ++;
}
}
qDebug() << "Record count in fixdb: " << recNum;

[Venkatesh V]

Or you can also use this,

QSqlQuery q;
q.prepare("SELECT COUNT (*) FROM TableName");
q.exec();
int rows= 0;
if (q.next()) {
rows= q.value(0).toInt();
}

[gabor53]

@Venkatesh-V
This worked.
Thank you.