remove unwanted method args

pgm.go

@@ -44,6 +44,21 @@ func (f Field) Count() Field {
 	return Field("COUNT(" + f.String() + ")")
 }
 
+// StringEscape will return a empty string for null value
+func (f Field) StringEscape() Field {
+	return Field("COALESCE(" + f.String() + ", '')")
+}
+
+// NumberEscape will return a zero string for null value
+func (f Field) NumberEscape() Field {
+	return Field("COALESCE(" + f.String() + ", 0)")
+}
+
+// BooleanEscape will return a false for null value
+func (f Field) BooleanEscape() Field {
+	return Field("COALESCE(" + f.String() + ", FALSE)")
+}
+
 // Avg fn wrapping of field
 func (f Field) Avg() Field {
 	return Field("AVG(" + f.String() + ")")