postgresql 判断字段是否为空select COALESCE(tran.rm_amt,0) rm_amtselect COALESCE(null, 0) as test结果test0版权声明：本文为xiuxiuzhuanshu原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接和本声明。原文链接：https://blog.csdn.net/xiuxiuzhuanshu/article/details/78731189