查看某张表的表结构

select t1.table_name,
t1.column_name,
t1.nullable,
t1.data_type || '(' || t1.data_length || ')',
t2.comments
from all_tab_cols t1, all_col_comments t2
where t1.table_name = t2.table_name
and t1.column_name = t2.column_name
and t1.table_name = 'MTL_MATERIAL_TRANSACTIONS';