multi row select from SQLite

[SeyMohsenFls]

Hi friends, i want to select at least two rows from SQL, but i can't, can you help me guys??

[artwaw]

@SeyMohsenFls Please show your code. How are you trying to do this?

[SeyMohsenFls]

@artwaw i can just get one number like this:

QSqlQuery q1;
    QString comp1= ui->lineEdit->text();
    QString comp2= ui->lineEdit_2->text();
q1.exec("SELECT ["+comp2+"] From Par_A WHERE C_id='"+comp1+"'");

but i want get a row of data from a table in SQL then move that to a matrix like this:

a[5]={0,5,9,7,3};

[artwaw]

@SeyMohsenFls I think the pair of [] is not necessary, you can just simplify query to "select "+comp2+"from Par_A where C_id="+comp1+";" - sqlite is quite relaxed. if course, if C_id is of type text ' use might be necessary.
When you run your original query - what does q1.lastQuery() return? What is the return value of q1.lastError().text()?

You can add qDebug() << q1.lastQuery(); qDebug() << q1.lastError().text(); after the exec, this should throw out results into the console.

As for processing results, QSqlQuery documentation webpage tells you how to proceed (I assume you want a list of int):

QVector<int> results;
while (q1.next()) {
   results.append(q1.value(0).toInt();
}

[SeyMohsenFls]

@artwaw
i got this from that qDebug:

"SELECT [4] From Par_A WHERE C_id='2'"
""

there is no error.
i have another question. how can i input the value of a query to a variable before check the query?
i wrote this code but it's wrong!

QSqlQuery q1;
q1.exec("SELECT ["+comp2+"] From Par_A WHERE C_id='"+comp1+"'");
double a=q1.value(0).toDouble();

if(q1.first() )
    {
     //i dont want write ****a=q1.value(0).toDouble();**** here!!!!!
    }
    else {
        ui->text1->setText("not found!!!!!!!!");
    }

[artwaw]

@SeyMohsenFls pls try to apply the query I wrote (leave the check code just in case I did something wrong). Do not forget the ; at the end.

You can't, while (query.next()) is the way to go as far as I can tell. Please read the documentation.

[SeyMohsenFls]

@artwaw
thank you. I read documentation and problem solved.