SPARK SQl中的DATEDIFF [英] DATEDIFF in SPARK SQl

问题描述

我是Spark SQL的新手.我们正在将数据从SQL Server迁移到Databricks. 我正在使用SPARK SQL.您能否为以下datefunctions建议如何在SPARK sql中实现以下功能.我可以看到datediff在spark sql中只给出了几天.

I am new to Spark SQL. We are migrating data from SQL server to Databricks. I am using SPARK SQL . Can you please suggest how to achieve below functionality in SPARK sql for the below datefunctions. I can see datediff gives only days in spark sql.

DATEDIFF(YEAR，StartDate，EndDate) DATEDIFF(Month，StartDate，EndDate) DATEDIFF(Quarter，StartDate，EndDate)

DATEDIFF(YEAR,StartDate,EndDate) DATEDIFF(Month,StartDate,EndDate) DATEDIFF(Quarter,StartDate,EndDate)

推荐答案

正如您提到的，SparkSQL确实支持DATEDIFF，但仅支持几天.我也要小心，因为参数似乎与Spark相反，即

As you have mentioned SparkSQL does support DATEDIFF but for days only. I would also be careful as it seems the parameters are the opposite way round for Spark, ie

--SQL Server
DATEDIFF ( datepart , startdate , enddate )

--Spark
DATEDIFF ( enddate , startdate )

Spark确实支持类似的功能，称为months_between，可以代替DATEDIFF( month ...来使用.此函数还会返回一个十进制数，因此可以选择将其强制转换为INT，以获得与

Spark does however support a similar function called months_between which you could use in place of DATEDIFF( month .... This function also returns a decimal amount so optionally cast it to INT for similar functionality to the

SELECT startDate, endDate, 
  DATEDIFF( endDate, startDate ) AS diff_days,
  CAST( months_between( endDate, startDate ) AS INT ) AS diff_months      
FROM yourTable
ORDER BY 1;

还有year和quarter函数，分别用于确定日期的年和季度.您可以简单地减去年份，但是季度会更加棘手.可能是您必须做数学"或最终使用日历表.

There are also year and quarter functions for determining the year and quarter of a date respectively. You could simply minus the years but quarters would be more tricky. It may be you have to 'do the math' or end up using a calendar table.

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