Question

以前主题的链接 - LINKED Oracle - runtime and show data based on inserted year ( not duplicate )

摘要

根据上面的链接，我继续编写更具体的结果我想要的，我在代码中遇到了一些问题使用“WHERE”语句显示使用后的特定数据替代变量（＆amp;）

根据Mr.Barboros提供的工作代码，我想添加一些查询，仅显示一些位置，例如，

我有查询2016，它应该只显示2个结果

FACILITYNAME COUNT_TIMES    MONTHS
Science Lab     1             4
Science Lab     1             5

但它总是显示额外的位置，即使在2016年也是生物学是没有生物学插入数据库。 - 如果我用“或”添加更多位置，它仍会继续显示结果，下面是我查询的代码。

SELECT f.FACILITYNAME,COUNT(*) AS count_times, EXTRACT (MONTH FROM b.Timebooked ) AS MONTHS
FROM BookingTable b
JOIN FacilityTable f ON b.FACILITYNO = f.FACILITYNO
WHERE TO_CHAR(b.Timebooked , 'YYYY') = 2018
AND f.FACILITYNAME = 'Toilet' OR f.FACILITYNAME = 'Science Lab' OR  f.FACILITYNAME = 'Biology Lab'
GROUP BY (EXTRACT (MONTH FROM b.Timebooked )),f.FACILITYNAME
ORDER BY (EXTRACT (MONTH FROM b.Timebooked ));

http://sqlfiddle.com/#!4/13a6a/9

我想要的结果是，当我进入任何一年时，只显示厕所，科学实验室生物学实验室

Answer 1

需要添加＆＃39;（）＆＃39;在＆＃39; OR＆＃39;周围条件。如果没有括号，AND将优先于OR。请参阅SQL Logic Operator Precedence。

试试这个：

SELECT f.FACILITYNAME,COUNT(*) AS count_times, EXTRACT (MONTH FROM b.Timebooked ) AS MONTHS
FROM BookingTable b
JOIN FacilityTable f ON b.FACILITYNO = f.FACILITYNO
WHERE TO_CHAR(b.Timebooked , 'YYYY') = 2018
AND (f.FACILITYNAME = 'Toilet' OR f.FACILITYNAME = 'Science Lab' OR  f.FACILITYNAME = 'Biology Lab')
GROUP BY (EXTRACT (MONTH FROM b.Timebooked )),f.FACILITYNAME
ORDER BY (EXTRACT (MONTH FROM b.Timebooked ));

如果没有括号，您的查询实际上是这样做的（这是不正确的）：

SELECT f.FACILITYNAME,COUNT(*) AS count_times, EXTRACT (MONTH FROM b.Timebooked ) AS MONTHS
FROM BookingTable b
JOIN FacilityTable f ON b.FACILITYNO = f.FACILITYNO
WHERE ( TO_CHAR(b.Timebooked , 'YYYY') = 2018
AND  f.FACILITYNAME = 'Toilet') OR f.FACILITYNAME = 'Science Lab' OR  f.FACILITYNAME = 'Biology Lab' 
GROUP BY (EXTRACT (MONTH FROM b.Timebooked )),f.FACILITYNAME
ORDER BY (EXTRACT (MONTH FROM b.Timebooked ));

特定数据查询

1 个答案: