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https://issues.apache.org/jira/browse/DRILL-1877?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14279184#comment-14279184
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Jinfeng Ni commented on DRILL-1877:
-----------------------------------
Before we make change, we probably need decide whether Drill will adopt MYSQL
way or Postgres way in handling the boolean operator.
Standard SQL has only "AND" "OR" "NOT" operators. Some system, for instance,
Mysql, will treat "&&" as "AND", "||" as "OR". While other system like
Postgre only has "AND", "OR". For mysql style, the use of "||" as "OR"
operator will overload the "||" operator, since it could be also used as string
concat.
http://dev.mysql.com/doc/refman/5.7/en/logical-operators.html
http://www.postgresql.org/docs/9.4/static/functions-logical.html
Therefore, the first question is whether we want to use "||" for both boolean
and string concat operator.
For your patch, you modify ExprParser.g. Seems ExprLexer.g will also need
change to be consistent. Both of them are handling the parsing of expression in
DRILL's logical/physical plan, and should be consistent in handling how we
handle "||" as either boolean or string operator.
> Throw unsupported error message for || operator early in the parsing stage
> --------------------------------------------------------------------------
>
> Key: DRILL-1877
> URL: https://issues.apache.org/jira/browse/DRILL-1877
> Project: Apache Drill
> Issue Type: Bug
> Components: SQL Parser
> Affects Versions: 0.7.0
> Reporter: Victoria Markman
> Assignee: Jinfeng Ni
> Priority: Minor
> Fix For: 0.9.0
>
> Attachments: DRILL-1877.1.patch, DRILL-1877.2.patch
>
>
> If we don't plan to support concat operator (||), we should throw a decent
> error message early.
> The error is cryptic:
> 0: jdbc:drill:schema=dfs> select cast(l_orderkey as varchar(10)) || '-' ||
> cast(l_partkey as varchar(10)) from cp.`tpch/lineitem.parquet`;
> Query failed: Query stopped., Line 65, Column 29: "value" is neither a
> method, a field, nor a member class of
> "org.apache.drill.exec.expr.holders.VarCharHolder" [
> bc85685d-e08a-494b-aa9f-5b3fa4ee4033 on atsqa4-133.qa.lab:3
> 1010 ]
> Error: exception while executing query: Failure while executing query.
> (state=,code=0)
> I believe that error that I'm getting from the query below is the result of
> not throwing "Unsupported" message earlier.
> Please correct me if I'm wrong.
> 0: jdbc:drill:schema=dfs> select
> . . . . . . . . . . . . > cast(l_orderkey as varchar(10)) || '-' ||
> cast(l_partkey as varchar(10))
> . . . . . . . . . . . . > from
> . . . . . . . . . . . . > (
> . . . . . . . . . . . . > select sum(l_quantity),
> . . . . . . . . . . . . > l_orderkey,
> . . . . . . . . . . . . > l_partkey
> . . . . . . . . . . . . > from cp.`tpch/lineitem.parquet`
> . . . . . . . . . . . . > group by
> . . . . . . . . . . . . > l_orderkey,
> . . . . . . . . . . . . > l_partkey
> . . . . . . . . . . . . > )
> . . . . . . . . . . . . > group by
> . . . . . . . . . . . . > cast(l_orderkey as varchar(10)) || '-' ||
> cast(l_partkey as varchar(10));
> Query failed: Query failed: Failure while running fragment., You tried to do
> a batch data read operation when you were in a state of STOP. You can only
> do this type of operation when you are in a state of OK or OK_NEW_SCHEMA. [
> f5cb68a8-7c05-4e02-a104-56081e6d34ce on atsqa4-133.qa.lab:31010 ]
> [ f5cb68a8-7c05-4e02-a104-56081e6d34ce on atsqa4-133.qa.lab:31010 ]
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