PostgreSQL/pgsql 为表添加列/ 判断列存不存在再添加列

1.通用方法: 
eg:

DO $$
    BEGIN
        BEGIN
            ALTER TABLE dingtalk_corp_info ADD COLUMN admin_id TEXT;
        EXCEPTION
            WHEN duplicate_column THEN RAISE NOTICE 'column admin_id already exists in dingtalk_corp_info.';
        END;
    END;
$$;

2.pgsql 9.6+: 
eg:

ALTER TABLE dingtalk_corp_info ADD COLUMN IF NOT EXISTS admin_id TEXT;

3.直接添加 
eg:

ALTER TABLE dingtalk_corp_info
ADD COLUMN admin_id TEXT;