I have an RDD containing a timestamp named time of type long:
root
|-- id: string (nullable = true)
|-- value1: string (nullable = true)
I'm using Spark 1.4.0 and since 1.2.0 DATE
appears to be present in the Spark SQL API (SPARK-2562). DATE
should allow you to group by the time as YYYY-MM-DD
.
I also have a similar data structure, where my created_on
is analogous to your time
field.
root
|-- id: long (nullable = true)
|-- value1: long (nullable = true)
|-- created_on: long (nullable = true)
I solved it using FROM_UNIXTIME(created_on,'YYYY-MM-dd')
and works well:
val countQuery = "SELECT FROM_UNIXTIME(created_on,'YYYY-MM-dd') as `date_created`, COUNT(*) AS `count` FROM user GROUP BY FROM_UNIXTIME(created_on,'YYYY-MM-dd')"
From here on you can do the normal operations, execute the query into a dataframe and so on.
FROM_UNIXTIME
worked probably because I have Hive included in my Spark installation and it's a Hive UDF. However it will be included as part of the Spark SQL native syntax in future releases (SPARK-8175).
Not sure if this is what you meant/needed but I've felt the same struggle-ness dealing with date/timestamp in spark-sql and the only thing I came up with was casting string in timestamp since it seems impossible (to me) having Date type in spark-sql.
Anyway, this is my code to accomplish something similar (Long in place of String) to your need (maybe):
val mySQL = sqlContext.sql("select cast(yourLong as timestamp) as time_cast" +
" ,count(1) total "+
" from logs" +
" group by cast(yourLong as timestamp)"
)
val result= mySQL.map(x=>(x(0).toString,x(1).toString))
and the output is something like this:
(2009-12-18 10:09:28.0,7)
(2009-12-18 05:55:14.0,1)
(2009-12-18 16:02:50.0,2)
(2009-12-18 09:32:32.0,2)
Could this be useful for you as well even though I'm using timestamp and not Date?
Hope it could help
FF
EDIT: in order to test a "single-cast" from Long to Timestamp I've tried this simple change:
val mySQL = sqlContext.sql("select cast(1430838439 as timestamp) as time_cast" +
" ,count(1) total "+
" from logs" +
" group by cast(1430838439 as timestamp)"
)
val result= mySQL.map(x=>(x(0),x(1)))
and all worked fine with the result:
(1970-01-17 14:27:18.439,4) // 4 because I have 4 rows in my table
I solved the issue by adding this function:
def convert( time:Long ) : String = {
val sdf = new java.text.SimpleDateFormat("yyyy-MM-dd")
return sdf.format(new java.util.Date(time))
}
And registering it into the sqlContext like this:
sqlContext.registerFunction("convert", convert _)
Then I could finally group by date:
select * from table convert(time)