diff --git a/src/sql/drivers/psql/qsql_psql.cpp b/src/sql/drivers/psql/qsql_psql.cpp
index c052e4c2e7..722595ad52 100644
--- a/src/sql/drivers/psql/qsql_psql.cpp
+++ b/src/sql/drivers/psql/qsql_psql.cpp
@@ -104,6 +104,11 @@
 #define QXIDOID 28
 #define QCIDOID 29
 
+#define QBITOID 1560
+#define QVARBITOID 1562
+
+#define VARHDRSZ 4
+
 /* This is a compile time switch - if PQfreemem is declared, the compiler will use that one,
    otherwise it'll run in this template */
 template <typename T>
@@ -533,17 +538,33 @@ QSqlRecord QPSQLResult::record() const
             f.setName(QString::fromUtf8(PQfname(d->result, i)));
         else
             f.setName(QString::fromLocal8Bit(PQfname(d->result, i)));
-        f.setType(qDecodePSQLType(PQftype(d->result, i)));
+        int ptype = PQftype(d->result, i);
+        f.setType(qDecodePSQLType(ptype));
         int len = PQfsize(d->result, i);
         int precision = PQfmod(d->result, i);
-        // swap length and precision if length == -1
-        if (len == -1 && precision > -1) {
-            len = precision - 4;
+
+        switch (ptype) {
+        case QNUMERICOID:
+            if (precision != -1) {
+                len = (precision >> 16);
+                precision = ((precision - VARHDRSZ) & 0xffff);
+            }
+            break;
+        case QBITOID:
+        case QVARBITOID:
+            len = precision;
             precision = -1;
+            break;
+        default:
+            if (len == -1 && precision >= VARHDRSZ) {
+                len = precision - VARHDRSZ;
+                precision = -1;
+            }
         }
+
         f.setLength(len);
         f.setPrecision(precision);
-        f.setSqlType(PQftype(d->result, i));
+        f.setSqlType(ptype);
         info.append(f);
     }
     return info;
diff --git a/tests/auto/sql/kernel/qsqlquery/tst_qsqlquery.cpp b/tests/auto/sql/kernel/qsqlquery/tst_qsqlquery.cpp
index 301c7bca51..824f042ffc 100644
--- a/tests/auto/sql/kernel/qsqlquery/tst_qsqlquery.cpp
+++ b/tests/auto/sql/kernel/qsqlquery/tst_qsqlquery.cpp
@@ -195,6 +195,9 @@ private slots:
     void task_233829_data() { generic_data("QPSQL"); }
     void task_233829();
 
+    void QTBUG_12477_data() { generic_data("QPSQL"); }
+    void QTBUG_12477();
+
     void sqlServerReturn0_data() { generic_data(); }
     void sqlServerReturn0();
 
@@ -3012,6 +3015,47 @@ void tst_QSqlQuery::task_233829()
     QVERIFY_SQL(q,exec());
 }
 
+void tst_QSqlQuery::QTBUG_12477()
+{
+    QFETCH(QString, dbName);
+    QSqlDatabase db = QSqlDatabase::database(dbName);
+    CHECK_DATABASE(db);
+    if (!db.driverName().startsWith("QPSQL"))
+        QSKIP("PostgreSQL specific test");
+
+    QSqlQuery q(db);
+    QVERIFY_SQL(q, exec("SELECT 1::bit, '10101010000111101101'::varbit, "
+                              "'10101111011'::varbit(15), '22222.20'::numeric(16,2), "
+                              "'333333'::numeric(18), '444444'::numeric"));
+    QVERIFY_SQL(q, next());
+    QSqlRecord r = q.record();
+    QSqlField f;
+
+    f = r.field(0);
+    QCOMPARE(f.length(), 1);
+    QCOMPARE(f.precision(), -1);
+
+    f = r.field(1);
+    QCOMPARE(f.length(), -1);
+    QCOMPARE(f.precision(), -1);
+
+    f = r.field(2);
+    QCOMPARE(f.length(), 15);
+    QCOMPARE(f.precision(), -1);
+
+    f = r.field(3);
+    QCOMPARE(f.length(), 16);
+    QCOMPARE(f.precision(), 2);
+
+    f = r.field(4);
+    QCOMPARE(f.length(), 18);
+    QCOMPARE(f.precision(), 0);
+
+    f = r.field(5);
+    QCOMPARE(f.length(), -1);
+    QCOMPARE(f.precision(), -1);
+}
+
 void tst_QSqlQuery::sqlServerReturn0()
 {
     QFETCH( QString, dbName );