针对STRUCT数据类型使用like运算符 [英] Using like operator against STRUCT data type

问题描述

我有一个带有结构数组的表.有没有一种方法可以使用like运算符从该列中过滤记录?

I have a table with array of structs. Is there a way to filter the records from this column using like operator ?

hive> desc location;
location_list           array<struct<city:string,state:string>>

hive> select * from location;
row1 : [{"city":"Hudson","state":"NY"},{"city":"San Jose","state":"CA"},{"city":"Albany","state":"NY"}]
row2 : [{"city":"San Jose","state":"CA"},{"city":"San Diego","state":"CA"}]

我正在尝试运行类似这样的查询，以仅过滤那些具有"NY"状态的记录.

I am trying to run a query something like this, to filter only those records with "NY" state.

hive> select * from location where location_list like '%"NY"%';
FAILED: SemanticException [Error 10014]: Line 1:29 Wrong arguments ''%"NY"%'': No matching method for class org.apache.hadoop.hive.ql.udf.UDFLike with (array<struct<city:string,state:string>>, string). Possible choices: _FUNC_(string, string)

注意:我可以通过进行侧视&此struct列爆炸.但是要避免这种情况，因为我需要将此表与另一个不接受横向视图的表连接起来.

Note : I could do this by doing a lateralview & explode of this struct column. But trying to avoid it because I need join this table with another where lateral view is not accepted.

推荐答案

很好的问题，您可以通过以下高效(美观)的方式来实现.

Nice question, you can do it in the following efficient ( and beautiful) way.

select * from location 
where array_contains(location_list.state, 'NY');

在这种情况下， location_list.state 将创建一个字符串数组(在您的情况下为状态)，因此您可以使用UDF array_contains 进行值检查.这将寻找确切的值，您将无法执行类似 like 运算符的匹配，但您应该能够实现所需的结果

In this case, location_list.state will create an array of strings (states in your case) so you can use the UDF array_contains for value checking. This will look for exact value, you will not be able to perform a matching like the like operator but you should be able to achieve what you are looking

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