如何写一段sql语句，可以检索出所有表的结构信息？

Question

desc user_tables;
desc user_col_comments;看看能不能满足你需要。

Answer 1

如：
SQL> select a.table_name,(select count(*) from user_tab_columns b 
  2  where a.table_name=b.table_name) colnum
  3  from user_tables a;TABLE_NAME                         COLNUM
------------------------------ ----------
A                                       1
AA_TEST_FUN                             1
ACCOUNT                                 2
B                                       1
BONUS                                   4
DEPT                                    3
EMP                                     8
PLAN_TABLE                             27
RECEIPT                                 1
SALGRADE                                3
T                                       2

Answer 2

或者
SQL> select table_name,count(*) column_num
  2  from user_tab_columns
  3  group by table_name;TABLE_NAME                     COLUMN_NUM
------------------------------ ----------
CCP                                    15
CCP_FILTER                             16
CCP_SAME_PHONE                         16
CZLINEBOX                              16
DEVICE                                  2
DP                                     14
DP_FILTER                              15
DP_SAME_PHONE                          15
EXPORT_FILE                             3
EXPORT_TIME                             2
FILTERDATE                              2
FILTER_BY_JJXNO_TIME                    4
FXHNO                                   5
FXHNO_FILTER                            5
JJXNO                                   4
JJXNO_FILTER                            4
LINECENTER                              2
MDF                                    15
MDF_FILTER                             16
MDF_SAME_PHONE                         16
PROCEDURE_ERROR_LOG                     3
PXJNO                                   6
PXJNO_FILTER                            6
TEST                                   15
USERLOG                                 6
USERMANAGER                             4
V1                                     15已选择27行。