text: -- OTC Sales Orders (completely same structure as `offer` table)
  CREATE TABLE IF NOT EXISTS `otc_offer` (
    id INT NOT NULL AUTO_INCREMENT,
    userId INT NOT NULL, -- generally it's OTC Sales provider admin's userId
    base CHAR(3) NOT NULL,
    counter CHAR(3) NOT NULL,
    buysell TINYINT NOT NULL DEFAULT 1, -- -1:sell 1:buy
    price DECIMAL(10,2) NOT NULL,
    qty BIGINT NOT NULL,
    remaining BIGINT NOT NULL,
    cancelled TINYINT NOT NULL DEFAULT 0, -- 0:NO, 1:Cancelled
    createdAt BIGINT NOT NULL,
    updatedAt BIGINT NOT NULL,
    PRIMARY KEY (id)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
  ALTER TABLE otc_offer ADD INDEX idx_otc_offer_userId(`userId`);
  ALTER TABLE otc_offer ADD INDEX idx_otc_offer_userOffers(`userId`,`base`,`counter`,`updatedAt`);
  ALTER TABLE otc_offer ADD INDEX idx_otc_offer_orderbook(`base`,`counter`,`price`,`remaining`,`cancelled`,`updatedAt`);
  ALTER TABLE otc_offer ADD INDEX idx_otc_offer_matchingOffer(`base`,`counter`,`price`,`buysell`,`remaining`,`cancelled`,`updatedAt`);
  -- otc_offer's original index:
  ALTER TABLE otc_offer ADD UNIQUE idx_otc_offer_userCpairBuysell(`userId`,`base`,`counter`,`buysell`);
  ALTER TABLE otc_offer ADD INDEX idx_otc_offer_userCpair(`userId`,`base`,`counter`);
  
  