Victoria Markman created DRILL-3769:
---------------------------------------
Summary: to_date function with one argument returns wrong data type
Key: DRILL-3769
URL: https://issues.apache.org/jira/browse/DRILL-3769
Project: Apache Drill
Issue Type: Bug
Reporter: Victoria Markman
1. to_date function is not part of SQL standard according to my research
(checked ISO/IEC9075-2), so implementations of it may vary from database to
database (our implementation of to_date is different from Postgres, for example)
2. Our documentation only talks about to_date with 2 parameters: format and
actual string to be converted to date type
3. Calcite does not seem to have to_date, which makes me think that this is
Drill UDF
4. Apparently, if you invoke to_date() with one argument in Drill: it runs.
So there are two possibilities: we implemented to_date with one argument to be
compatible with some other SQL engine, Hive ?
or
it is a bug and we should throw an error.
You can use to_date with one argument in a simple query:
{code}
0: jdbc:drill:schema=dfs> select to_date(c1 + interval '1' day) from t1 limit 1;
+-------------+
| EXPR$0 |
+-------------+
| 2015-01-02 |
+-------------+
1 row selected (0.242 seconds)
{code}
However, since return type is varbinary, joins, aggregations and CTAS are going
to be problematic.
Here is to_date use in join to illustrate this (c1 is a date column):
{code}
0: jdbc:drill:schema=dfs> select * from t1, t2 where to_date(t1.c1) = t2.c2;
Error: SYSTEM ERROR: DrillRuntimeException: Join only supports implicit casts
between 1. Numeric data
2. Varchar, Varbinary data 3. Date, Timestamp data Left type: DATE, Right
type: VAR16CHAR. Add explicit casts to avoid this error
Fragment 0:0
[Error Id: 66ac8248-56c5-401a-aa53-de90cb828bc4 on atsqa4-133.qa.lab:31010]
(state=,code=0)
{code}
Since we don't support cast between varbinary and date, attempt to cast it
results in:
{code}
0: jdbc:drill:schema=dfs> select * from t1, t2 where cast(to_date(t1.c1) as
date) = t2.c2;
Error: SYSTEM ERROR: SchemaChangeException: Failure while trying to materialize
incoming schema. Errors:
Error in expression at index -1. Error: Missing function implementation:
[castBIGINT(VAR16CHAR-OPTIONAL)]. Full expression: --UNKNOWN EXPRESSION--..
Fragment 0:0
[Error Id: deeb040a-f1d3-4ea0-8849-7ced29508576 on atsqa4-133.qa.lab:31010]
(state=,code=0)
{code}
Same with CTAS:
{code}
0: jdbc:drill:schema=dfs> create table x(a1) as select to_date(c1) from t1;
+-----------+----------------------------+
| Fragment | Number of records written |
+-----------+----------------------------+
| 0_0 | 10 |
+-----------+----------------------------+
1 row selected (0.4 seconds)
0: jdbc:drill:schema=dfs> select * from x;
+--------------+
| a1 |
+--------------+
| [B@28b5395d |
| [B@11c91d8c |
| [B@2ab2db73 |
| [B@446570eb |
| [B@5fd87761 |
| [B@7c85b26f |
| [B@2d85d547 |
| [B@2d753faa |
| null |
| [B@6ca6c936 |
+--------------+
10 rows selected (0.183 seconds)
0: jdbc:drill:schema=dfs> select cast(a1 as date) from x;
Error: SYSTEM ERROR: IllegalFieldValueException: Value 0 for monthOfYear must
be in the range [1,12]
Fragment 0:0
[Error Id: 71d8cd8f-6c88-4a13-9d24-b06ef52f6572 on atsqa4-133.qa.lab:31010]
(state=,code=0)
{code}
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