diff --git a/jOOQ/src/main/java/org/jooq/types/DayToSecond.java b/jOOQ/src/main/java/org/jooq/types/DayToSecond.java
index fb01fbfcff..59099a1cd4 100644
--- a/jOOQ/src/main/java/org/jooq/types/DayToSecond.java
+++ b/jOOQ/src/main/java/org/jooq/types/DayToSecond.java
@@ -96,7 +96,14 @@ public final class DayToSecond extends Number implements Interval, Comparable<Da
     private final int            nano;
 
     /**
-     * Create a new day-hour interval.
+     * Create a new interval.
+     */
+    public DayToSecond() {
+        this(0, 0, 0, 0, 0, false);
+    }
+
+    /**
+     * Create a new day interval.
      */
     public DayToSecond(int days) {
         this(days, 0, 0, 0, 0, false);
@@ -110,21 +117,21 @@ public final class DayToSecond extends Number implements Interval, Comparable<Da
     }
 
     /**
-     * Create a new day-hour interval.
+     * Create a new day-minute interval.
      */
     public DayToSecond(int days, int hours, int minutes) {
         this(days, hours, minutes, 0, 0, false);
     }
 
     /**
-     * Create a new day-hour interval.
+     * Create a new day-second interval.
      */
     public DayToSecond(int days, int hours, int minutes, int seconds) {
         this(days, hours, minutes, seconds, 0, false);
     }
 
     /**
-     * Create a new day-hour interval.
+     * Create a new day-nanoseconds interval.
      */
     public DayToSecond(int days, int hours, int minutes, int seconds, int nano) {
         this(days, hours, minutes, seconds, nano, false);
@@ -494,12 +501,17 @@ public final class DayToSecond extends Number implements Interval, Comparable<Da
     @Override
     public final int hashCode() {
         final int prime = 31;
-        int result = 1;
-        result = prime * result + days;
-        result = prime * result + hours;
-        result = prime * result + minutes;
-        result = prime * result + nano;
-        result = prime * result + seconds;
+        int result = 0;
+        if (days != 0)
+            result = prime * result + days;
+        if (hours != 0)
+            result = prime * result + hours;
+        if (minutes != 0)
+            result = prime * result + minutes;
+        if (nano != 0)
+            result = prime * result + nano;
+        if (seconds != 0)
+            result = prime * result + seconds;
         return result;
     }
 
@@ -509,20 +521,24 @@ public final class DayToSecond extends Number implements Interval, Comparable<Da
             return true;
         if (obj == null)
             return false;
-        if (getClass() != obj.getClass())
+        if (getClass() == obj.getClass()) {
+            DayToSecond other = (DayToSecond) obj;
+            if (days != other.days)
+                return false;
+            if (hours != other.hours)
+                return false;
+            if (minutes != other.minutes)
+                return false;
+            if (nano != other.nano)
+                return false;
+            if (seconds != other.seconds)
+                return false;
+            return true;
+        }
+        else if (obj instanceof YearToSecond)
+            return obj.equals(this);
+        else
             return false;
-        DayToSecond other = (DayToSecond) obj;
-        if (days != other.days)
-            return false;
-        if (hours != other.hours)
-            return false;
-        if (minutes != other.minutes)
-            return false;
-        if (nano != other.nano)
-            return false;
-        if (seconds != other.seconds)
-            return false;
-        return true;
     }
 
     @Override
diff --git a/jOOQ/src/main/java/org/jooq/types/YearToMonth.java b/jOOQ/src/main/java/org/jooq/types/YearToMonth.java
index bdf036ae9d..992b0c57ba 100644
--- a/jOOQ/src/main/java/org/jooq/types/YearToMonth.java
+++ b/jOOQ/src/main/java/org/jooq/types/YearToMonth.java
@@ -87,6 +87,13 @@ public final class YearToMonth extends Number implements Interval, Comparable<Ye
     private final int            years;
     private final int            months;
 
+    /**
+     * Create a new year-month interval.
+     */
+    public YearToMonth() {
+        this(0, 0, false);
+    }
+
     /**
      * Create a new year-month interval.
      */
@@ -237,9 +244,11 @@ public final class YearToMonth extends Number implements Interval, Comparable<Ye
     @Override
     public final int hashCode() {
         final int prime = 31;
-        int result = 1;
-        result = prime * result + months;
-        result = prime * result + years;
+        int result = 0;
+        if (months != 0)
+            result = prime * result + months;
+        if (years != 0)
+            result = prime * result + years;
         return result;
     }
 
@@ -249,14 +258,18 @@ public final class YearToMonth extends Number implements Interval, Comparable<Ye
             return true;
         if (obj == null)
             return false;
-        if (getClass() != obj.getClass())
+        if (getClass() == obj.getClass()) {
+            YearToMonth other = (YearToMonth) obj;
+            if (months != other.months)
+                return false;
+            if (years != other.years)
+                return false;
+            return true;
+        }
+        else if (obj instanceof YearToSecond)
+            return obj.equals(this);
+        else
             return false;
-        YearToMonth other = (YearToMonth) obj;
-        if (months != other.months)
-            return false;
-        if (years != other.years)
-            return false;
-        return true;
     }
 
     @Override
diff --git a/jOOQ/src/main/java/org/jooq/types/YearToSecond.java b/jOOQ/src/main/java/org/jooq/types/YearToSecond.java
index 4973cb468e..c5aec087a3 100644
--- a/jOOQ/src/main/java/org/jooq/types/YearToSecond.java
+++ b/jOOQ/src/main/java/org/jooq/types/YearToSecond.java
@@ -90,8 +90,8 @@ public final class YearToSecond extends Number implements Interval, Comparable<Y
     private final DayToSecond dayToSecond;
 
     public YearToSecond(YearToMonth yearToMonth, DayToSecond dayToSecond) {
-        this.yearToMonth = yearToMonth == null ? new YearToMonth(0) : yearToMonth;
-        this.dayToSecond = dayToSecond == null ? new DayToSecond(0) : dayToSecond;
+        this.yearToMonth = yearToMonth == null ? new YearToMonth() : yearToMonth;
+        this.dayToSecond = dayToSecond == null ? new DayToSecond() : dayToSecond;
     }
 
     /**
@@ -334,9 +334,13 @@ public final class YearToSecond extends Number implements Interval, Comparable<Y
     @Override
     public int hashCode() {
         final int prime = 31;
-        int result = 1;
-        result = prime * result + ((dayToSecond == null) ? 0 : dayToSecond.hashCode());
-        result = prime * result + ((yearToMonth == null) ? 0 : yearToMonth.hashCode());
+        int result = 0;
+        int h1 = dayToSecond.hashCode();
+        int h2 = yearToMonth.hashCode();
+        if (h1 != 0)
+            result = prime * result + h1;
+        if (h2 != 0)
+            result = prime * result + h2;
         return result;
     }
 
@@ -346,22 +350,34 @@ public final class YearToSecond extends Number implements Interval, Comparable<Y
             return true;
         if (obj == null)
             return false;
-        if (getClass() != obj.getClass())
-            return false;
-        YearToSecond other = (YearToSecond) obj;
-        if (dayToSecond == null) {
-            if (other.dayToSecond != null)
+        if (getClass() == obj.getClass()) {
+            YearToSecond other = (YearToSecond) obj;
+            if (dayToSecond == null) {
+                if (other.dayToSecond != null)
+                    return false;
+            }
+            else if (!dayToSecond.equals(other.dayToSecond))
                 return false;
-        }
-        else if (!dayToSecond.equals(other.dayToSecond))
-            return false;
-        if (yearToMonth == null) {
-            if (other.yearToMonth != null)
+            if (yearToMonth == null) {
+                if (other.yearToMonth != null)
+                    return false;
+            }
+            else if (!yearToMonth.equals(other.yearToMonth))
                 return false;
+            return true;
         }
-        else if (!yearToMonth.equals(other.yearToMonth))
+        else if (obj instanceof YearToMonth) {
+            YearToMonth other = (YearToMonth) obj;
+            return getDayToSecond().intValue() == 0 &&
+                   getYearToMonth().equals(other);
+        }
+        else if (obj instanceof DayToSecond) {
+            DayToSecond other = (DayToSecond) obj;
+            return getYearToMonth().intValue() == 0 &&
+                   getDayToSecond().equals(other);
+        }
+        else
             return false;
-        return true;
     }
 
     @Override