[英]How to do a Full Outer Join using old style Oracle syntax
I have two tables with the same columns, Item Code and Qty, for each Table: 我有两个表,每个表都有相同的列,分别是项代码和数量:
TABLE A TABLE B
-------------- -------------
X 2 X 1
Y 1 S 2
Z 5 Z 5
The result that I am aiming to get is something like this: 我想要得到的结果是这样的:
Table C
---------------
X 2 1
Y 1 0
S 0 2
I only need the items where qty
differs in both tables (including the nulls which should be shown as zeroes. 我只需要两个表中
qty
不同的项目(包括应该显示为零的null)。
Note: I am using Oracle8 so I can't use the ANSI FULL OUTER JOIN. 注意:我正在使用Oracle8,所以不能使用ANSI FULL OUTER JOIN。
Edit, Since the question is specific to Oracle 8 which does not use ANSI syntax, the following should work: 编辑,由于该问题是特定于不使用ANSI语法的Oracle 8的,因此以下各项应适用:
select col1,
nvl(a_col2, 0) as a_col2,
nvl(b_col2, 0) as b_col2
from
(
select a.col1, a.col2 as a_col2, b.col2 as b_col2
from TableA a, TableB b
where a.col1 = b.col1(+)
union
select b.col1, a.col2 as a_col2, b.col2 as b_col2
from TableA a, TableB b
where a.col1(+) = b.col1
)
where a_col2 <> b_col2
or (a_col2 is null or b_col2 is null)
See SQL Fiddle with Demo . 请参阅带有演示的SQL Fiddle 。 This will return:
这将返回:
| COL1 | A_COL2 | B_COL2 |
--------------------------
| S | 0 | 2 |
| X | 2 | 1 |
| Y | 1 | 0 |
If you are using a version of Oracle that supports ANSI syntax then you can use the following FULL OUTER JOIN
: 如果使用的是支持ANSI语法的Oracle版本,则可以使用以下
FULL OUTER JOIN
:
select
coalesce(a.col1, b.col1) col1,
coalesce(a.col2, 0) a_col2,
coalesce(b.col2, 0) b_col2
from tablea a
full outer join tableb b
on a.col1 = b.col1
where a.col2 <> b.col2
or (a.col2 is null or b.col2 is null);
Another writing of the query which should work in 8 and (probably earlier versions). 该查询的另一种写法应在8及更高版本(可能是较早的版本)中运行。
It uses neither FULL JOIN
not the horrible (+)
syntax for joins so it should work even when an upgrade deprecates it. 它既不使用
FULL JOIN
也不使用可怕的(+)
语法进行联接,因此即使升级已弃用它,它也应能正常工作。
Assuming that there are no Nulls already on the tables, you won't need COALESCE()
or NVL()
either: 假设表上没有Null,则您将不需要
COALESCE()
或NVL()
:
SELECT a.col1,
a.col2 AS a_col2,
b.col2 AS b_col2
FROM TableA a, TableB b
WHERE a.col1 = b.col1
AND ( a.col2 <> b.col2
OR a.col2 IS NULL
OR b.col2 IS NULL
)
UNION ALL
SELECT col1, col2, 0
FROM TableA a
WHERE NOT EXISTS
( SELECT *
FROM TableB b
WHERE a.col1 = b.col1
)
UNION ALL
SELECT col1, 0, col2
FROM TableB b
WHERE NOT EXISTS
( SELECT *
FROM TableA a
WHERE a.col1 = b.col1
) ;
Tests at SQL-Fiddle 在SQL-Fiddle中进行测试
Another option: 另外一个选项:
select
full_list.item_code,
nvl(table_a.qty,0) table_a_qty,
nvl(table_b.qty,0) table_b_qty
from
(select item_code from table_a
union
select item_code from table_b) full_list,
table_a,
table_b
where
full_list.item_code = table_a.item_code(+) and
full_list.item_code = table_b.item_code(+)
The following query should work just right: 以下查询应该可以正常工作:
SELECT * FROM (
SELECT nvl(a.c1, b.c2), nvl(a.col1, 0) qty1, nvl(b.col2, 0) qty2 FROM a FULL OUTER JOIN b ON a.c1 = b.c2
) where qty1 != qty2;
http://sqlfiddle.com/#!4/d37ff/5/0 http://sqlfiddle.com/#!4/d37ff/5/0
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