Hive check next row

Question

I am writing a hive query to check the next record for every userid. For ex: for userid U1, if the key is same (K1) for the next record, then update the classify column for the row as manual match , but if the user's next record's has different key then leave it blank

userid category  timestamp              key classify
U1      imported 04-02-2016 05:02:01    k1  NULL
U2      deleted  04-02-2016 05:00:00    k3  NULL
U1      matched  04-02-2016 04:49:00    k1  **manual match**
U4      imported 04-02-2016 04:50:01    k1  NULL
U3      matched  04-02-2016 04:48:00    k2  NULL
U4      matched  04-02-2016 04:47:00    k4  **NULL**

I am trying to start with this

select LEAD(description) OVER (PARTITION BY userid order by timestamp ROWS BETWEEN CURRENT ROW AND 1 FOLLOWING) from adithya.smartmatching where subcategory = 'SmartExpense Imported'

and then implement a case condition for the classify column. But I am getting an error for the above code itself. Can somebody help me?

Getting error : Your query has the following error(s):

Your query has the following error(s): Error while compiling statement: FAILED: SemanticException Failed to breakup Windowing invocations into Groups. At least 1 group must only depend on input columns. Also check for circular dependencies. Underlying error: Expecting left window frame boundary for function LEAD((TOK_TABLE_OR_COL description)) Window Spec=[PartitioningSpec=[partitionColumns=[(TOK_TABLE_OR_COL userid)]orderColumns=[(TOK_TABLE_OR_COL timestamp) ASC]]window(start=currentRow, end=range(1 FOLLOWING))] as _wcol0 to be unbounded. Found : 0

Thanks

Answer 1

have you created partition in table adithya.smartmatching .if yes then you must not used partition by select LEAD(description) OVER ( PARTITION BY userid order by timestamp ROWS BETWEEN CURRENT ROW AND 1 FOLLOWING) from adithya.smartmatching where subcategory = 'SmartExpense Imported'

after removing partition by (partition) its work.used like select LEAD(description) OVER (PARTITION (userid) order by timestamp ROWS BETWEEN CURRENT ROW AND 1 FOLLOWING) from adithya.smartmatching where subcategory = 'SmartExpense Imported'