-- =============================================================================
-- 为 CRM 业务管线（线索/商机/项目）增加「对接人职位」字段 contact_position
--
-- 说明：
--   - 幂等：列已存在时自动跳过，不会报 Duplicate column 错误；
--   - 只增加字段，不改动任何已有数据；
--   - 若尚未建表，直接执行 yz_backend_crm_pipeline.sql 已包含该字段，无需本脚本。
-- =============================================================================

SET NAMES utf8mb4;

-- 1. 线索
SET @has_col := (SELECT COUNT(*) FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'yz_backend_crm_clue' AND COLUMN_NAME = 'contact_position');
SET @sql := IF(@has_col = 0,
  'ALTER TABLE `yz_backend_crm_clue` ADD COLUMN `contact_position` varchar(50) NOT NULL DEFAULT '''' COMMENT ''对接人职位'' AFTER `contact_person`',
  'SELECT ''skip: yz_backend_crm_clue.contact_position 已存在'' AS note');
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;

-- 2. 商机
SET @has_col := (SELECT COUNT(*) FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'yz_backend_crm_business' AND COLUMN_NAME = 'contact_position');
SET @sql := IF(@has_col = 0,
  'ALTER TABLE `yz_backend_crm_business` ADD COLUMN `contact_position` varchar(50) NOT NULL DEFAULT '''' COMMENT ''对接人职位'' AFTER `contact_person`',
  'SELECT ''skip: yz_backend_crm_business.contact_position 已存在'' AS note');
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;

-- 3. 项目
SET @has_col := (SELECT COUNT(*) FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'yz_backend_crm_project' AND COLUMN_NAME = 'contact_position');
SET @sql := IF(@has_col = 0,
  'ALTER TABLE `yz_backend_crm_project` ADD COLUMN `contact_position` varchar(50) NOT NULL DEFAULT '''' COMMENT ''对接人职位'' AFTER `contact_person`',
  'SELECT ''skip: yz_backend_crm_project.contact_position 已存在'' AS note');
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;

-- 4. 核对：三张表的 contact_position 字段
SELECT TABLE_NAME, COLUMN_NAME, COLUMN_TYPE, COLUMN_COMMENT
FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = DATABASE()
  AND TABLE_NAME IN ('yz_backend_crm_clue', 'yz_backend_crm_business', 'yz_backend_crm_project')
  AND COLUMN_NAME = 'contact_position'
ORDER BY TABLE_NAME;