-- 客户主表增加合同开始时间、合同结束时间
-- 供应商只增加合同结束时间；合同开始时间与原有合作开始日期重复，已有列则删除
-- 客户列已存在时不要重复执行前面的 ALTER
SET NAMES utf8mb4;

-- 先去掉供应商上后加的合同开始时间，避免后续语句失败时这一列还留着
SET @has_supplier_contract_start := (
  SELECT COUNT(*) FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = 'sup_supplier'
    AND COLUMN_NAME = 'contract_start_date'
);
SET @drop_supplier_contract_start := IF(
  @has_supplier_contract_start > 0,
  'ALTER TABLE sup_supplier DROP COLUMN contract_start_date',
  'SELECT 1'
);
PREPARE drop_supplier_contract_start_stmt FROM @drop_supplier_contract_start;
EXECUTE drop_supplier_contract_start_stmt;
DEALLOCATE PREPARE drop_supplier_contract_start_stmt;

ALTER TABLE ctr_customer
  ADD COLUMN contract_start_date date DEFAULT NULL COMMENT '合同开始时间' AFTER credit_ed,
  ADD COLUMN contract_end_date date DEFAULT NULL COMMENT '合同结束时间' AFTER contract_start_date;

-- 供应商原有合作开始日期，只补合同结束时间（已有则跳过）
SET @has_supplier_contract_end := (
  SELECT COUNT(*) FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = 'sup_supplier'
    AND COLUMN_NAME = 'contract_end_date'
);
SET @add_supplier_contract_end := IF(
  @has_supplier_contract_end = 0,
  'ALTER TABLE sup_supplier ADD COLUMN contract_end_date date DEFAULT NULL COMMENT ''合同结束时间'' AFTER cooperation_start_date',
  'SELECT 1'
);
PREPARE add_supplier_contract_end_stmt FROM @add_supplier_contract_end;
EXECUTE add_supplier_contract_end_stmt;
DEALLOCATE PREPARE add_supplier_contract_end_stmt;