What is the difference between the ALL_TAB_COLUMNS and ALL_TAB_COLS system tables in Oracle 12c? In my DB, the ALL_TAB_COLUMNS has slightly fewer rows than ALL_TAB_COLS.
From the Oracle manual for ALL_TAB_COLS
This view differs from "ALL_TAB_COLUMNS" in that system-generated hidden columns and invisible columns, which are user-generated hidden columns, are not filtered out.
From the Oracle manual for ALL_TAB_COLUMNS
This view filters out system-generated hidden columns and invisible columns, which are user-generated hidden columns. The ALL_TAB_COLS view does not filter out hidden columns and invisible columns
ALL_TAB_COLUMNS lists only user-defined columns whereas ALL_TAB_COLS also seems to contain some system columns in each user table that are not normally visible.
来源：https://stackoverflow.com/questions/26790333/difference-between-sys-all-tab-columns-and-sys-all-tab-cols-in-oracle-12c