[英]What does this oracle SQL syntax mean?
I'm trying to get Power BI to import some oracle SQL data, but it seems I have to modernize some of it's syntax.我试图让 Power BI 导入一些 oracle SQL 数据,但似乎我必须对其某些语法进行现代化改造。 I can't seem to figure out what this means:
我似乎无法弄清楚这意味着什么:
(
( SELECT
t1.column1
FROM
table1 t1
WHERE
t1.column3 = something
)
+
( SELECT
t2.column2
FROM
table2 t2
WHERE
t2.column3 = somethingelse
)
) AS name
It's the +-sign in the middle that throws me.是中间的 + 号让我感到震惊。 I've already learned that there's an old syntax for OUTER JOIN that uses a WHERE-clause with (+)-symbol to denote left/right, but this doesn't follow the syntax as there's no WHERE-clause.
我已经了解到 OUTER JOIN 有一种旧语法,它使用带 (+) 符号的 WHERE 子句来表示左/右,但这不遵循语法,因为没有 WHERE 子句。 Maybe it's just some regular SQL syntax that I've never seen before.
也许这只是一些我以前从未见过的常规 SQL 语法。 Please enlighten me?
请赐教?
As @astentx stated in his comment , (SELECT... FROM...)
is a scalar sub-query and the +
operator is adding the numeric values that are returned from the sub-queries.正如@astentx 在他的评论中所述,
(SELECT... FROM...)
是一个标量子查询, +
运算符正在添加从子查询返回的数值。
You could equally have written it as:你同样可以把它写成:
( SELECT t1.column1 +
FROM table1 t1
CROSS JOIN t2.column2
WHERE t1.column3 = something
AND t2.column3 = somethingelse
) AS name
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