Question 90315 in PostgreSQL Question posted in
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Query in QT doesn't get any data – Postgresql

This is rows in my table.
SQL table

With this code, I get "in" in console.

QSqlQuery qry;
qry.prepare("SELECT * FROM user");
qry.exec();
if(qry.size() > 0)
    qInfo() << "in";
else
    qInfo() << "error";

But with this code, I get "error".

QSqlQuery qry;
qry.prepare("SELECT age FROM user");
qry.exec();
if(qry.size() > 0)
    qInfo() << "in";
else
    qInfo() << "error";
Tags:

2

Answers


  1. 0 
    QSqlQuery qry;
qry.prepare("SELECT age FROM user");
if(qry.exec()) {
    while(qry.next()) {
        qInfo()<<"in";
    }
} else {
    qInfo()<<"error";
}
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  2. 0

    Try

    QSqlQuery qry;
qry.prepare("SELECT age FROM "user"");
qry.exec();

    The problem is with the table name. Since user is a reserved word, some tools (PgAdmin) automatically add double quotes to the name "user" and you have to use double quotes when applying to the table. Unfortunately user in Postgres is a function (equivalent to current_user) hence the first query returns a row without error.

    The best solution is to rename the table and not use reserved words as Postgres identifiers (the name of a table, column, view, function, etc).

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