我从“hadoop权威指南”中阅读了以下代码：

SELECT a.ad_id, a.campaign_id, a.account_id, b.user_id
FROM dim_ads a JOIN impression_logs b ON (b.ad_id = a.ad_id)
WHERE b.dateid = '2008-12-01') x
INSERT OVERWRITE DIRECTORY 'results_gby_adid'
SELECT x.ad_id, count(1), count(DISTINCT x.user_id) GROUP BY x.ad_id
INSERT OVERWRITE DIRECTORY 'results_gby_campaignid'
SELECT x.campaign_id, count(1), count(DISTINCT x.user_id) GROUP BY x.campaign_id
INSERT OVERWRITE DIRECTORY 'results_gby_accountid'
SELECT x.account_id, count(1), count(DISTINCT x.user_id) GROUP BY x.account_id;

但是作为我的测试，使用几个不同的方法不能得到正确的结果。
我的hiveql如下：

CREATE TABLE IF NOT EXISTS a (logindate int, id int);

然后将本地文件加载到此表。。。

CREATE TABLE IF NOT EXISTS user (id INT) PARTITIONED BY (logindate INT) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' STORED AS TEXTFILE;

如果单独插入表格：

INSERT OVERWRITE TABLE user PARTITION(logindate=20130120) SELECT DISTINCT(id) FROM a WHERE logindate=20130120;
INSERT OVERWRITE TABLE user PARTITION(logindate=20130121) SELECT DISTINCT(id) FROM a WHERE logindate=20130121;

结果正确；
但如果选择下一个多重插入hql：

FROM a
INSERT OVERWRITE TABLE user PARTITION(logindate=20130120) SELECT DISTINCT(id) WHERE logindate=20130120
INSERT OVERWRITE TABLE user PARTITION(logindate=20130121) SELECT DISTINCT(id) WHERE logindate=20130121;
the results are not correct, both partitions have the same number of records, seems like select from DISTINCT(id) WHERE logindate=20130120 OR logindate=20130121

那么，这是一个错误还是我写了一些错误的语法？