Sql 是否按“选择”部分中的“强制转换”字段分组？

在我的主选择部分中有一个字段，我想在报告中按该字段分组

CAST((SELECT attribute_value.attrib_value_name 
FROM attribute_value,
attribute_type 
WHERE attribute_type.attrib_type_code = 'SC17' 
AND attribute_type.attrib_type_code = attribute_value.attrib_type_code 
AND attribute_value.attrib_value_code = feat_attrib_type.attrib_value_code  ) as VARCHAR (30)) as ZONE_SPEC,

我曾尝试将相同的代码放在SQL的group部分，但它总是返回一条错误消息

“ORA-00933:SQL命令未正确结束”

到目前为止，我得到的代码是：

select

CAST((SELECT attribute_value.attrib_value_name 
FROM attribute_value,
attribute_type 
WHERE attribute_type.attrib_type_code = 'SC17' 
AND attribute_type.attrib_type_code = attribute_value.attrib_type_code 
AND attribute_value.attrib_value_code = feat_attrib_type.attrib_value_code  ) as VARCHAR (30)) as ZONE_SPEC,
feature_type.feature_type_name,

sum (feat_measurement.feature_quantity)


from
feature
inner join feature_type on feature.feature_type_code = feature_type.feature_type_code
inner join area on feature.area_code = area.area_code
inner join feat_measurement on feature.plot_number = feat_measurement.plot_number 
and feature.site_code = feat_measurement.site_code
inner join measurement_type on feat_measurement.measurement_code = measurement_type.measurement_code
inner join feat_attrib_type on feature.site_code = feat_attrib_type.site_code AND
feature.plot_number = feat_attrib_type.plot_number

where
measurement_type.measurement_code in ('AREA') and
feature.feature_deadflag = 'N'

group by 
CAST((SELECT attribute_value.attrib_value_name 
FROM attribute_value,
attribute_type 
WHERE attribute_type.attrib_type_code = 'SC17' 
AND attribute_type.attrib_type_code = attribute_value.attrib_type_code 
AND attribute_value.attrib_value_code = feat_attrib_type.attrib_value_code  ) as VARCHAR (30)) as ZONE_SPEC,

feature_type.feature_type_name

order by
feature_type.feature_type_name

---

是否可以将此强制转换字段添加到分组字段中？如果是这样的话，怎么做？

如果您试图在GROUPBY子句中投射表达式，我认为这是不允许的。但是，您可以通过使用分区来实现所需的结果。我已经编辑了一点代码

select
feature_type.feature_type_name,
sum (feat_measurement.feature_quantity) OVER (Partition by CAST((SELECT attribute_value.attrib_value_name 
FROM attribute_value,
attribute_type 
WHERE attribute_type.attrib_type_code = 'SC17' 
AND attribute_type.attrib_type_code = attribute_value.attrib_type_code 
AND attribute_value.attrib_value_code = feat_attrib_type.attrib_value_code  ) as VARCHAR (30)))as ZONE_SPEC

from
feature
inner join feature_type on feature.feature_type_code = feature_type.feature_type_code
inner join area on feature.area_code = area.area_code
inner join feat_measurement on feature.plot_number = feat_measurement.plot_number 
and feature.site_code = feat_measurement.site_code
inner join measurement_type on feat_measurement.measurement_code = measurement_type.measurement_code
inner join feat_attrib_type on feature.site_code = feat_attrib_type.site_code AND
feature.plot_number = feat_attrib_type.plot_number

where
measurement_type.measurement_code in ('AREA') and
feature.feature_deadflag = 'N'

group by 
feat_measurement.feature_quantity,
feat_attrib_type.attrib_value_code,
feature_type.feature_type_name

order by
feature_type.feature_type_name

---

希望这有帮助。

今天的提示：切换到现代的显式

JOIN

语法。更易于编写（无错误）、更易于读取和维护，并且在需要时更易于转换为外部联接。跳过GROUP BY的列别名尝试

作为ZONE_SPEC

。当我尝试按ZONE_SPEC分组时，feature_type.feature_type_name会收到错误消息ORA-00904：“ZONE_SPEC”：无效标识使用

联接

。我认为不能通过子查询进行聚合。