Explode the Array of Struct in Hive

问题

This is the below Hive Table

CREATE EXTERNAL TABLE IF NOT EXISTS SampleTable
(
USER_ID BIGINT,
NEW_ITEM ARRAY<STRUCT<PRODUCT_ID: BIGINT,TIMESTAMPS:STRING>>
)

And this is the data in the above table-

1015826235     [{"product_id":220003038067,"timestamps":"1340321132000"},{"product_id":300003861266,"timestamps":"1340271857000"}]

Is there any way I can get the below output from the HiveQL after exploding the array?

**USER_ID**  |  **PRODUCT_ID**  |   **TIMESTAMPS**
 ------------+------------------+----------------
1015826235      220003038067       1340321132000
1015826235      300003861266       1340271857000

Updated

I wrote this query to get the output in the above format, but it is not giving me the result in the way I wanted to.

SELECT myTable1.myCol1,myTable2.myCol2 FROM sampletable st LATERAL VIEW 
explode(st.purchased_item.product_id) myTable1 AS myCol1 LATERAL VIEW 
explode(st.purchased_item.timestamps) myTable2 AS myCol2;

Can anyone help me what wrong I am doing? Any suggestions will be appreciated.

回答1:

You need to explode only once (in conjunction with LATERAL VIEW). After exploding you can use a new column (called prod_and_ts in my example) which will be of struct type. Then, you can resolve the product_id and timestamps members of this new struct column to retrieve the desired result.

SELECT
   user_id,
   prod_and_ts.product_id as product_id,
   prod_and_ts.timestamps as timestamps
FROM 
   SampleTable 
   LATERAL VIEW explode(new_item) exploded_table as prod_and_ts;

回答2:

If you are on Hive 0.10 or later, you could also use inline(ARRAY<STRUCT[,STRUCT]>). It explodes an array of structs into a table.

来源：https://stackoverflow.com/questions/11373543/explode-the-array-of-struct-in-hive

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