查看当前用户下有哪些表(找表)
select table_name from user_tab_comments;
查看当前用户下的表记录数(查看记录数)
select table_name, num_rows from user_tables where num_rows > 0 order by num_rows desc;
查看当前用户下有哪些字段(根据字段名找表)
select table_name, column_name from user_tab_columns where instr(column_name, '列名关键字')>0;