diff --git a/set.go b/set.go
index ec44177..3636693 100644
--- a/set.go
+++ b/set.go
@@ -19,21 +19,27 @@ func SetInt(val int) null.Int {
 	}
 }
 
-func SetBool(val bool) null.Bool {
+func SetBool(val bool) (res null.Bool) {
 	return null.Bool{
 		Bool:  val,
 		Valid: true,
 	}
 }
 
-func SetTime(val time.Time) null.Time {
+func SetTime(val time.Time) (res null.Time) {
+	if val.IsZero() {
+		return
+	}
 	return null.Time{
 		Time:  val,
 		Valid: true,
 	}
 }
 
-func SetJSON(val []byte) null.JSON {
+func SetJSON(val []byte) (res null.JSON) {
+	if val == nil {
+		return
+	}
 	return null.JSON{
 		JSON:  val,
 		Valid: true,