选择出的信息结果：表名 说明
select user_tab_comments.table_name as 表名,ments as 说明 from user_tab_comments
选择出的信息结果：表名（备注）、列名、列标注、主键、外键、字段类型、长度、小数位数、是否允许空、默认值
selectcasewhen ments is null then a.table_nameelse a.table_name||'('||ments||')'end as 表名（备注）,a.column_name as 列名,ments as 列标注,decode(e.key1, 'P', '√', '') as 主键,decode(e.key2, 'R', '√', '') as 外键,a.data_type as 字段类型,NVL(decode(a.data_type, 'NUMBER', a.data_precision, a.data_length),0) as 长度,NVL(a.data_scale,0) as 小数位数,a.nullable as 是否为空,a.data_default as 默认值fromuser_tab_columns a,user_col_comments f,user_tab_comments,( selectuc.table_name,uc.constraint_name,ucc.column_name,uc.constraint_type key1,uc.constraint_type key2fromuser_constraints uc,user_cons_columns uccwhere(uc.constraint_type='R'or uc.constraint_type='P')and uc.constraint_name=ucc.constraint_nameand uc.owner=ucc.ownerand uc.table_name=ucc.table_nameand ucc.table_name not like 'BIN$%==$0') ewherea.table_name = e.table_name(+)and a.column_name = e.column_name(+)and a.table_name = f.table_nameand a.column_name = f.column_nameand a.table_name = user_tab_comments.table_nameand a.table_name not like 'BIN$%==$0'order by a.table_name
