1,  ORACLE 查询表结构

SELECT table_name, column_name, data_type,DATA_LENGTH,COLUMN_ID,user_tab_comments,user_col_comments FROM USER_TAB_COLUMNS WHERE table_name =upper('T_Acc_Settle_Account');

SELECT * FROM user_tab_columns WHERE table_name='T_Acc_Settle_Account';

SELECT * FROM all_tab_cols WHERE table_name =upper('T_Acc_Settle_Account');

2,  查看oracle单个数据表包含的索引

SELECT * FROM user_indexes WHERE table_name=upper('T_Acc_Settle_Account');

 
3,  查看哪些表哪些字段包含指定类型

SELECT table_name, column_name, data_type,DATA_LENGTH,COLUMN_ID FROM all_tab_cols WHERE data_type =upper('NVARCHAR2');

4, 查询列的备注说明

SELECT * FROM user_col_comments WHERE table_name =upper('T_Acc_Settle_Account');

5,  查询表的备注说明

SELECT * FROM user_tab_comments WHERE table_name =upper('t_acc_merch_day_count');

6,  查询表里前100条数据，类似于mysql的limit

SELECT * FROM T_Acc_Settle_Account WHERE rownum<100;