在Hive中使用Month()在MM中使用Month [英] Month in MM using Month() in Hive

问题描述

Select * from concat(YEAR(DATE_SUB(MAX(Column_name),60),MONTH(DATE_SUB(MAX(Column_name),60),-01)

month()在直到9月的几个月内仅产生一位数字，即Jan返回1而不是01.在处理此问题时需要帮助.

The month() yields only single digit for months until September i.e Jan returns 1 instead of 01. Need help in handling this.

我正在使用此输出使用TO_DATE馈送给另一个SELECT查询.

I am using this output to feed to another SELECT query using TO_DATE.

推荐答案

month()函数返回整数，这就是为什么不存在前导零的原因.您可以使用lpad(month,2,0)函数格式化月份:

month() function returns integer, that is why there is no leading zero. You can use lpad(month,2,0) function to format month:

hive> select lpad(month('2017-09-01'),2,0);
OK
09
Time taken: 0.124 seconds, Fetched: 1 row(s)
hive> select lpad(month('2017-10-01'),2,0);
OK
10
Time taken: 0.433 seconds, Fetched: 1 row(s)

或者，您可以使用substr()从日期中提取年份和月份:

Alternatively you can use substr() to extract year and month from the date:

hive> select substr('2017-10-01',1,4) as year, substr('2017-10-01',6,2) as month;
OK
year    month
2017    10

Hive 2.1.0之前的

date_sub()函数(HIVE-13248)返回类型为String，因为创建方法时不存在Date类型.参见此处: https://cwiki.apache.org/confluence/display/Hive/LanguageManual + UDF

date_sub() function prior to Hive 2.1.0 (HIVE-13248) return type was a String because no Date type existed when the method was created. See here: https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF

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