ALTER TABLE "mailbox"."mail"
    ADD COLUMN "distribute_time" date,
  ADD COLUMN "three_sign_time" date,
  ADD COLUMN "submit_completion_time" date;

COMMENT ON COLUMN "mailbox"."mail"."distribute_time" IS '省厅下发时间';

COMMENT ON COLUMN "mailbox"."mail"."three_sign_time" IS '所队专班签收时间';

COMMENT ON COLUMN "mailbox"."mail"."submit_completion_time" IS '提交办结时间';