Hive LEAD Function: Usage & Syntax Guide

1 year ago
Sophia Anderson
1 minute

In Hive, the lead function is used to retrieve the value of the next row in a specified column. It can be used in conjunction with window functions to view the value of the next row in the result set.

The syntax of the lead function is as follows:

LEAD (value_expression [, offset [, default]]) OVER ( [ PARTITION BY partition_expression ] [ ORDER BY order_expression ] )

Among them:

  1. value_expression: The column or expression from which to retrieve the value of the next row.
  2. Offset: an optional parameter that determines the offset of the next row to be viewed, with a default value of 1.
  3. Default: Optional parameter that returns the default value when there is no next row.
  4. PARTITION BY: Optional clause used to specify the partition key.
  5. ORDER BY: an optional clause used to specify the sorting order.

举个例子，假设有一个表orders包含订单信息，包括订单号和订单金额。要查找每个订单的下一个订单金额，可以使用lead函数：

SELECT order_id, order_amount, LEAD(order_amount, 1) OVER (ORDER BY order_id) AS next_order_amount
FROM orders;

The above query will display the order number, order amount, and the amount of the next order for each order.

bannerAds