oracle中dual缩写是什么?
发布网友
发布时间：2022-05-02 00:56
共2个回答
热心网友
时间：2022-05-03 03:12
1: DUAL table-- a special kind of one-row and one-column database table;
2:al is a table which is created by oracle along with the data dictionary. It consists of exactly one column whose name is mmy and one record. The value of that record is X.
3:Note that the outer query references the mmy table called al the al table is used in Oracle when you need to run SQL that does not logically have a table name.
参考资料：http://www.dba-oracle.com/sql/t_al_table.htm
热心网友
时间：2022-05-03 04:30
