ODBC: fix loss of milliseconds when binding QDateTime

Caused by operator precedence error.

Follow-up to commit b8b79a0f37ec74fd5b4ad829e522a384ba3622ae

Task-number: QTBUG-2192
Change-Id: I17decd18c469b48a0bc938ae05c16cced8042219
Reviewed-by: Mark Brand <[email protected]>
(cherry-picked from qtbase commit 36b6d4afc970a328cced87af3d39b70d327eb3ad)
Reviewed-by: Andy Shaw <[email protected]>

Author: israelins85

src/sql/drivers/odbc/qsql_odbc.cpp

@@ -1413,7 +1413,7 @@ bool QODBCResult::exec()
 
                     // (How many leading digits do we want to keep?  With SQL Server 2005, this should be 3: 123000000)
                     int keep = (int)qPow(10.0, 9 - qMin(9, precision));
-                    dt->fraction /= keep * keep;
+                    dt->fraction = (dt->fraction / keep) * keep;
                 }
 
                 r = SQLBindParameter(d->hStmt,

tests/auto/qsqlquery/tst_qsqlquery.cpp

@@ -3294,14 +3294,19 @@ void tst_QSqlQuery::QTBUG_2192()
         QSqlQuery q(db);
         QVERIFY_SQL(q, exec("CREATE TABLE " + tableName + " (dt DATETIME)"));
 
+        QDateTime dt = QDateTime(QDate(2012, 7, 4), QTime(23, 59, 59, 999));
         QVERIFY_SQL(q, prepare("INSERT INTO " + tableName + " (dt) VALUES (?)"));
-        q.bindValue(0, QVariant(QDateTime(QDate(2012, 7, 4), QTime(23, 59, 59, 999))));
+        q.bindValue(0, dt);
         QVERIFY_SQL(q, exec());
 
-        // Check if value was stored with at least second precision.
         QVERIFY_SQL(q, exec("SELECT dt FROM " + tableName));
         QVERIFY_SQL(q, next());
-        QVERIFY(q.value(0).toDateTime().msecsTo(QDateTime(QDate(2012, 7, 4), QTime(23, 59, 59, 999))) < 1000 );
+
+        // Check if retrieved value preserves reported precision
+        int precision = qMax(0, q.record().field("dt").precision());
+        int diff = qAbs(q.value(0).toDateTime().msecsTo(dt));
+        int keep = qMin(1000, (int)qPow(10.0, precision));
+        QVERIFY(diff <= 1000 - keep);
     }
 }