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From Veera Naranammalpuram <vnaranammalpu...@maprtech.com>
Subject Re: to_date(csv-columns[x],'yyyy-mm-dd') - IllegalArgumentException
Date Fri, 28 Oct 2016 15:47:48 GMT
That should work and a lot faster too. Thanks for the pointer.

-Veera

On Fri, Oct 28, 2016 at 11:43 AM, Andries Engelbrecht <
aengelbrecht@maprtech.com> wrote:

> Good catch on empty string Veera!
>
> Wouldn't it be cheaper to check for an empty string?
> case when columns[] ='' then null else to_date(columns[],'yyyy-MM-dd') end
>
> I don't think the option to read csv empty columns (or empty string in any
> text reader) as null is in the reader yet. So we can't check with columns[]
> is null.
>
>
> --Andries
>
>
> > On Oct 28, 2016, at 8:21 AM, Veera Naranammalpuram <
> vnaranammalpuram@maprtech.com> wrote:
> >
> > Do you have zero length strings in your data? I have seen cases where the
> > system option to cast empty strings to NULL doesn't work as advertised.
> You
> > should re-open DRILL-3214.
> >
> > When I run into this problem, I usually use a regex to workaround. The
> > PROJECT takes a performance hit when you do this for larger data sets but
> > it works.
> >
> > $cat nulls.psv
> > date_col|string_col
> > |test
> > 2016-10-28|test2
> > $ sqlline
> > apache drill 1.8.0
> > "a little sql for your nosql"
> > 0: jdbc:drill:> select date_col, string_col from `nulls.psv`;
> > +-------------+-------------+
> > |  date_col   | string_col  |
> > +-------------+-------------+
> > |             | test        |
> > | 2016-10-28  | test2       |
> > +-------------+-------------+
> > 2 rows selected (0.303 seconds)
> > 0: jdbc:drill:> select to_date(date_col,'yyyy-mm-dd') from `nulls.psv`;
> > Error: SYSTEM ERROR: IllegalArgumentException: Invalid format: ""
> >
> > Fragment 0:0
> >
> > [Error Id: c058acbe-f2bf-4c3b-a447-66bebdc4c642 on
> se-node10.se.lab:31010]
> > (state=,code=0)
> > 0: jdbc:drill:>  select case when date_col similar to '[0-9]+%' then
> > to_date(date_col,'yyyy-MM-dd') else null end as date_col_converted from
> > `nulls.psv`;
> > +---------------------+
> > | date_col_converted  |
> > +---------------------+
> > | null                |
> > | 2016-10-28          |
> > +---------------------+
> > 2 rows selected (0.521 seconds)
> > 0: jdbc:drill:> alter system set
> > `drill.exec.functions.cast_empty_string_to_null` = true;
> > +-------+----------------------------------------------------------+
> > |  ok   |                         summary                          |
> > +-------+----------------------------------------------------------+
> > | true  | drill.exec.functions.cast_empty_string_to_null updated.  |
> > +-------+----------------------------------------------------------+
> > 1 row selected (0.304 seconds)
> > 0: jdbc:drill:>  select to_date(date_col,'yyyy-mm-dd') from `nulls.psv`;
> > Error: SYSTEM ERROR: IllegalArgumentException: Invalid format: ""
> >
> > Fragment 0:0
> >
> > [Error Id: 92126a1b-1c03-4e90-bc3a-01c5c81bb013 on
> se-node10.se.lab:31010]
> > (state=,code=0)
> > 0: jdbc:drill:>
> >
> > -Veera
> >
> > On Fri, Oct 28, 2016 at 9:24 AM, Khurram Faraaz <kfaraaz@maprtech.com>
> > wrote:
> >
> >> All,
> >>
> >> Question is - why does it work for a parquet column and fails when CSV
> >> column is used ?
> >>
> >> Drill 1.9.0 commit : a29f1e29
> >>
> >> This is a simple project of column from a csv file, works.
> >> {noformat}
> >> 0: jdbc:drill:schema=dfs.tmp> select columns[4] FROM `typeall_l.csv` t1
> >> limit 5;
> >> +-------------+
> >> |   EXPR$0    |
> >> +-------------+
> >> | 2011-11-04  |
> >> | 1986-10-22  |
> >> | 1992-09-10  |
> >> | 2016-08-07  |
> >> | 1986-01-25  |
> >> +-------------+
> >> 5 rows selected (0.26 seconds)
> >> {noformat}
> >>
> >> Using TO_DATE function with columns[x] as first input fails, with an
> >> IllegalArgumentException
> >> {noformat}
> >> 0: jdbc:drill:schema=dfs.tmp> select to_date(columns[4],'yyyy-mm-dd')
> FROM
> >> `typeall_l.csv` t1 limit 5;
> >> Error: SYSTEM ERROR: IllegalArgumentException: Invalid format: ""
> >>
> >> Fragment 0:0
> >>
> >> [Error Id: 9cff3eb9-4045-4d9a-a6a1-1eadaa597f30 on
> centos-01.qa.lab:31010]
> >> (state=,code=0)
> >> {noformat}
> >>
> >> However, interestingly same query over parquet column returns correct
> >> results, on same data.
> >>
> >> {noformat}
> >> 0: jdbc:drill:schema=dfs.tmp> select to_date(col_dt,'yyyy-mm-dd') FROM
> >> typeall_l limit 5;
> >> +-------------+
> >> |   EXPR$0    |
> >> +-------------+
> >> | 2011-01-04  |
> >> | 1986-01-22  |
> >> | 1992-01-10  |
> >> | 2016-01-07  |
> >> | 1986-01-25  |
> >> +-------------+
> >> 5 rows selected (0.286 seconds)
> >> {noformat}
> >>
> >> When the date string is passed as first input, to_date function returns
> >> correct results.
> >> {noformat}
> >> 0: jdbc:drill:schema=dfs.tmp> select to_date('2011-01-04','yyyy-mm-dd')
> >> from (values(1));
> >> +-------------+
> >> |   EXPR$0    |
> >> +-------------+
> >> | 2011-01-04  |
> >> +-------------+
> >> 1 row selected (0.235 seconds)
> >> {noformat}
> >>
> >> Thanks,
> >> Khurram
> >>
> >
> >
> >
> > --
> > Veera Naranammalpuram
> > Product Specialist - SQL on Hadoop
> > *MapR Technologies (www.mapr.com <http://www.mapr.com>)*
> > *(Email) vnaranammalpuram@maprtech.com <naranammalpuram@maprtech.com>*
> > *(Mobile) 917 683 8116 - can text *
> > *Timezone: ET (UTC -5:00 / -4:00)*
>
>


-- 
Veera Naranammalpuram
Product Specialist - SQL on Hadoop
*MapR Technologies (www.mapr.com <http://www.mapr.com>)*
*(Email) vnaranammalpuram@maprtech.com <naranammalpuram@maprtech.com>*
*(Mobile) 917 683 8116 - can text *
*Timezone: ET (UTC -5:00 / -4:00)*

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