查找其他oracle表中不存在的记录

Question

我试图找到表A中但不在表B中的记录.如果只有一列要检查,那么我可以使用

select col_A,col_B,......from A where col_A not in (select Col_A from B).

但我有四列需要检查.

我做了类似这样的事情,虽然有效,但并不是完美的方式

select col_A,col_B,col_C,col_D from A where col_A||col_B||col_C||col_D not in (select col_A||col_B||col_C||col_D from B)

并且在大量数据的情况下返回结果也需要很多时间.

请建议正确的方法.

谢谢.....

Answer 1

来自Oracle文档

http://docs.oracle.com/cd/E11882_01/server.112/e26088/queries004.htm#SQLRF52341

"MINUS示例以下语句将结果与MINUS运算符组合在一起,该运算符仅返回第一个查询返回的唯一行,但不返回第二个查询:

SELECT product_id FROM inventories
MINUS
SELECT product_id FROM order_items;

你的要求有点复杂.我假设,cols_a,cols_b,cols_c,cols_d的组合对于表A中的记录是唯一的.在这种情况下,以下代码应该可以解决您的问题:

create table A (
  cols_date DATE,
  cols_a NUMBER,
  cols_b NUMBER,
  cols_c NUMBER,
  cols_d NUMBER
);

create table B (
  cols_a NUMBER,
  cols_b NUMBER,
  cols_c NUMBER,
  cols_d NUMBER
);

insert into A (cols_date, cols_a, cols_b, cols_c, cols_d) values (sysdate, 1, 1, 1, 1);
insert into A (cols_date, cols_a, cols_b, cols_c, cols_d) values (sysdate, 2, 2, 2, 2);

insert into B (cols_a, cols_b, cols_c, cols_d) values (2, 2, 2, 2);
insert into B (cols_a, cols_b, cols_c, cols_d) values (3, 3, 3, 3);
commit;

select a.cols_date, a.cols_a, a.cols_b, a.cols_c, a.cols_d from (
  select cols_a, cols_b, cols_c, cols_d
  from A
  minus 
  select cols_a, cols_b, cols_c, cols_d
  from b
) ma, a
where 1=1
  and ma.cols_a = a.cols_a
  and ma.cols_b = a.cols_b
  and ma.cols_c = a.cols_c
  and ma.cols_d = a.cols_d;

结果是

COLS_DATE                 COLS_A     COLS_B     COLS_C     COLS_D
--------------------- ---------- ---------- ---------- ----------
01.07.2013 13:20:02            1          1          1          1 

NOT EXISTS也将解决问题.此语句具有比MINUS版本更好的执行计划.

感谢David Aldridge的解决方案.

select
  cols_date,
  cols_a, cols_b, cols_c, cols_d
from
  a
where
  not exists (
    select 1
    from   b
    where  1=1
  and b.cols_a = a.cols_a
  and b.cols_b = a.cols_b
  and b.cols_c = a.cols_c
  and b.cols_d = a.cols_d           
);