这是我的Hive查询,直接来自TPC-DS工具包:
WITH customer_total_return
AS (SELECT sr_customer_sk AS ctr_customer_sk,
sr_store_sk AS ctr_store_sk,
Sum(sr_fee) AS ctr_total_return
FROM store_returns,
date_dim
WHERE sr_returned_date_sk = d_date_sk
AND d_year = 2000
GROUP BY sr_customer_sk,
sr_store_sk)
SELECT TOP 100 c_customer_id
FROM customer_total_return ctr1,
store,
customer
WHERE ctr1.ctr_total_return > (SELECT Avg(ctr_total_return) * 1.2
FROM customer_total_return ctr2
WHERE ctr1.ctr_store_sk = ctr2.ctr_store_sk)
AND s_store_sk = ctr1.ctr_store_sk
AND s_state = 'TN'
AND ctr1.ctr_customer_sk = c_customer_sk
ORDER BY c_customer_id;
但是,尝试运行它时出现以下错误:
失败:ParseException 行 11:11 无法识别"TOP"附近的输入 选择目标中的"100"c_customer_id">
我的理解是TOP 100
在 HiveQL 中语法上无效。如何正确重写?
使用 LIMIT 而不是 TOP,如下所示:
WITH customer_total_return
AS (SELECT sr_customer_sk AS ctr_customer_sk,
sr_store_sk AS ctr_store_sk,
Sum(sr_fee) AS ctr_total_return
FROM store_returns,
date_dim
WHERE sr_returned_date_sk = d_date_sk
AND d_year = 2000
GROUP BY sr_customer_sk,
sr_store_sk)
SELECT c_customer_id
FROM customer_total_return ctr1,
store,
customer
WHERE ctr1.ctr_total_return > (SELECT Avg(ctr_total_return) * 1.2
FROM customer_total_return ctr2
WHERE ctr1.ctr_store_sk = ctr2.ctr_store_sk)
AND s_store_sk = ctr1.ctr_store_sk
AND s_state = 'TN'
AND ctr1.ctr_customer_sk = c_customer_sk
ORDER BY c_customer_id
LIMIT 100;
这是许多级别的查询的坏示例。 我建议:
WITH customer_total_return AS (
SELECT sr.sr_customer_sk AS ctr_customer_sk,
sr.sr_store_sk AS ctr_store_sk,
SUM(sr.sr_fee) AS ctr_total_return,
AVG(SUM(sr.sr_fee)) OVER (PARTITION BY sr.sr_store_sk) as avg_store_sr_fee
FROM store_returns sr JOIN
date_dim d
ON sr.sr_returned_date_sk = d.d_date_sk
WHERE d_year = 2000
GROUP BY sr_customer_sk, sr_store_sk
)
SELECT c.c_customer_id
FROM customer_total_return ctr JOIN
store s
ON s.s_store_sk = ctr.ctr_store_sk JOIN
customer c
ON ctr.ctr_customer_sk = c.c_customer_sk
WHERE ctr.ctr_total_return > 1.2 * avg_store_sr_fee AND
s.s_state = 'TN'
ORDER BY c.c_customer_id
LIMIT 100;
笔记:
- 切勿在
FROM
子句中使用逗号。始终使用正确、明确、标准JOIN
语法。 - 限定所有列引用,尤其是当查询具有多个表引用时。
- 不需要用于计算平均值的子查询。
- 蜂巢使用
LIMIT
,而不是TOP
。