我有以下SQL代码(这是我到目前为止已经有多少):
var bookRecords = from c in doc.Descendants("Book")
select new { bookCardNo = c.Element("CardNo").Value };
var LibraryRecords = from d in doc.Descendants("Library")
select new { libCardNo = d.Element("CardNo").Value,
rackno = d.Element("RackNo").Value };
var groupedRecords =
from br in bookRecords
join lr in LibraryRecords
on br.bookCardNo equals lr.libCardNo
select lr.rackno;
以下是VIEW_1的定义:
MERGE INTO SCHEMA1.TABLE_1 table1 USING
(
SELECT DISTINCT table2.column1,
view1.column2
FROM SCHEMA2.TABLE_2 table2
LEFT JOIN SCHEMA2.VIEW_1 view1
ON table2.column2 = view1.column3
) t2 ON (table1.column3 = t2.column1 )
WHEN MATCHED THEN
UPDATE
SET table1.column4 = t2.column2;
但我收到以下错误消息:
CREATE VIEW SCHEMA_2.VIEW_1
AS (SELECT
SCHEMA_2.TABLE_1.COLUMN_1,
SCHEMA_2.TABLE_2.COLUMN_1,
SCHEMA_2.TABLE_2.COLUMN_2,
SCHEMA_2.TABLE_2.COLUMN_3,
SCHEMA_2.TABLE_5.COLUMN_1,
SCHEMA_2.TABLE_6.COLUMN_1,
SCHEMA_2.TABLE_6.COLUMN_2,
SCHEMA_2.TABLE_6.COLUMN_3,
SCHEMA_2.TABLE_6.COLUMN_4,
SCHEMA_2.TABLE_7.COLUMN_1,
SCHEMA_2.TABLE_7.COLUMN_2,
SCHEMA_2.TABLE_8.COLUMN_1
FROM SCHEMA_2.TABLE_1
INNER JOIN SCHEMA_2.TABLE_2
ON SCHEMA_2.TABLE_1.COLUMN_1 = SCHEMA_2.TABLE_2.COLUMN_2
INNER JOIN SCHEMA_2.TABLE_5
ON SCHEMA_2.TABLE_1.COLUMN_4 = SCHEMA_2.TABLE_5.COLUMN_3
LEFT OUTER JOIN SCHEMA_2.TABLE_6
ON SCHEMA_2.TABLE_2.COLUMN_2 = SCHEMA_2.TABLE_6.COLUMN_4
LEFT OUTER JOIN SCHEMA_2.TABLE_7
ON SCHEMA_2.TABLE_2.COLUMN_1 = SCHEMA_2.TABLE_8.COLUMN_5
);
导致错误的原因是什么?在哪里更改代码以使其工作?
感谢您的帮助!
答案 0 :(得分:3)
对于此示例,您的问题肯定在USING子查询中。此查询会生成多个table2.column1
:
SELECT DISTINCT table2.column1,
view1.column2
FROM SCHEMA2.TABLE_2 table2
LEFT JOIN SCHEMA2.VIEW_1 view1
ON table2.column2 = view1.column3
因此ON子句将多次匹配table1
中的相同行:
ON (table1.column3 = t2.column1 )
Oracle无法确定在UPDATE中应使用t2.column2
的哪个值,因此它会抛出ORA-30926
。
在子查询中使用distinct无济于事,因为这会给出所有列的排列。您需要编写一个子查询,该子查询将在所有行中生成t2.column1
的唯一值,或者添加另一个标识列以生成可以加入table1
的唯一键。
答案 1 :(得分:1)
根据我的经验,这个错误不仅在USING子句为MATCH表中的一行返回多行时返回,而且还经常在它不能确定时只返回一行将被返回(即使没有返回多行的实际情况)。为了强制解析器在这种情况下接受查询,我通常会在MATCH..ON列上使用GROUP BY。
MERGE INTO SCHEMA1.TABLE_1 table1 USING
(
SELECT table2.column1,
MAX(view1.column2) as column2
FROM SCHEMA2.TABLE_2 table2
LEFT JOIN SCHEMA2.VIEW_1 view1
ON table2.column2 = view1.column3
GROUP BY table2.column1
) t2 ON (table1.column3 = t2.column1 )
WHEN MATCHED THEN
UPDATE
SET table1.column4 = t2.column2;