oracle表结构和表内容差异比对

oracle表结构和表内容差异比对

oracle中有三种集合操作,他们会把左边和右边的select 结果集进行集合操作.

• union 并集
• intersect 交集
• minus 差集

假设有如下两张表 STUDENT_A 和 STUDENT_B

create table STUDENT_A
(
  id   VARCHAR2(36) not null,
  name VARCHAR2(100),
  age  NUMBER,
  sex  VARCHAR2(2)
);  

insert into STUDENT_A (id, name, age, sex)
values ('', 'bobo', 28, '');
insert into STUDENT_A (id, name, age, sex)
values ('', 'sisi', 29, '');
commit;  

create table STUDENT_B
(
  id    VARCHAR2(36) not null,
  name  VARCHAR2(100),
  age   NUMBER,
  clazz VARCHAR2(36)
);  

insert into STUDENT_B (id, name, age, clazz)
values ('', 'bobo', 28, '');
insert into STUDENT_B (id, name, age, clazz)
values ('', 'sisi', 29, '');
insert into STUDENT_B (id, name, age, clazz)
values ('', 'kiki', 30, '');
commit; 

效果图如下:

比较两表结构差异语句:

注意下面的小括号不能省,因为是从左到右计算的,如果省掉计算公式就不一样了哦,大家可以自行脑补.

(
  SELECT column_name FROM user_tab_columns WHERE table_name = 'STUDENT_A'
  MINUS
  SELECT COLUMN_name FROM user_tab_columns WHERE table_name = 'STUDENT_B'
)
UNION
(
  SELECT column_name FROM user_tab_columns WHERE table_name = 'STUDENT_B'
  MINUS
  SELECT COLUMN_name FROM user_tab_columns WHERE table_name = 'STUDENT_A'
)

结果图如下:

比较两表内容语句:

注意下面的小括号不能省,因为是从左到右计算的,如果省掉计算公式就不一样了哦,大家可以自行脑补.

(
  SELECT * FROM  STUDENT_A
  MINUS
  SELECT * FROM  STUDENT_B
)
UNION
(
  SELECT * FROM  STUDENT_B
  MINUS
  SELECT * FROM  STUDENT_A
)

结果图如下:

同上图可知比较内容的时候,是不关心字段名是否有差异的,它只关心字段的类型和值.