Field, date truncate method

pgm_field.go

@@ -131,6 +131,16 @@ func (f Field) IsNotNull() Conditioner {
 	return &Cond{Field: col, op: " IS NOT NULL", len: len(col) + 12}
 }
 
+// DateTrunc will truncate date or timestamp to specified level of precision
+//
+// Level values:
+//   - microseconds, milliseconds, second, minute, hour
+//   - day, week (Monday start), month, quarter, year
+//   - decade, century, millennium
+func (f Field) DateTrunc(level, as string) Field {
+	return Field("DATE_TRUNC('" + level + "', " + f.String() + ") AS " + as)
+}
+
 // EqualFold will use LOWER(column_name) = LOWER(val) for comparision
 func (f Field) EqFold(val string) Conditioner {
 	col := f.String()