Count the number of tables in the system and query the field information of all tables

Count the number of tables in the system and query the field information of all tables -- count the number of tables in the system: -- table description field: -- required field: Name, Code, Commente select lower (. TABLE_NAME) | '-' | B. comments, lower (. TABLE_NAME), B. comments from user_tables a, user_tab_comments B where. TABLE_NAME = B. TABLE_NAME order by B. comments,. TABLE_NAME; -- query the field information of all tables. -- Name, Code, Data Type, Length, P, F, comments select. table_name, t. comments,. COLUMN_ID, nvl (B. comments, B. column_name), B. column_name,. DATA_TYPE, case when. DATA_TYPE = 'varchar2' then. DATA_TYPE | '(' |. DATA_LENGTH | ')' when. DATA_TYPE = 'date' then'' when. DATA_TYPE = 'number' and. DATA_SCALE is not null then. DATA_TYPE | '(' |. DATA_PRECISION | ',' |. DATA_SCALE | ')' when. DATA_TYPE = 'number' and. DATA_SCALE is null then. DATA_TYPE | '(' |. DATA_LENGTH | ') 'else' end case, case when (select nvl (count (1), 0) from user_cons_columns c, user_constraints d where d. constraint_name = c. constraint_name and d. constraint_type = 'p' and c. table_name =. table_name and c. column_name =. column_name) = 1 then nvl (select d. constraint_name from user_cons_columns c, user_constraints d where d. constraint_name = c. constraint_name and d. constraint_type = 'p' and c. table_name =. table_name and c. column_name =. column_name), '') else'' end case from user_tab_cols a, user_col_comments B, user_tab_comments t where. TABLE_NAME = B. table_name and. COLUMN_NAME = B. column_name and. table_name = t. table_name order by. table_name,. COLUMN_ID;