不同于 MySQL，请检查 from 之前显示的字段，尤其是 AS 命名符号的引用。
在 Oracle 中单引 AS ‘XXX’ 是错误的，需要修改为双引 "XXX" 或者是干脆去掉 ‘‘
select t.user_name as ‘name‘ from user t;
select t.user_name as "name" from user t;
select t.user_name as name from user t;
Oracle ORA-00923: FROM keyword not found where expected
原文：https://www.cnblogs.com/niceyoo/p/11973958.html