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https://issues.apache.org/jira/browse/DRILL-197?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13755937#comment-13755937
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Julian Hyde commented on DRILL-197:
-----------------------------------

What Jacques said.

Other ways of quoting identifiers are possible -- e.g. MySQL uses back-ticks, 
MSSql uses brackets -- but double-quotes is the most common. It is used by 
Oracle, Teradata, Postgres.

No SQL-compliant database allows double-quotes for character literals. (MySQL 
and Hive, I'm looking at you.)

I agree that double-quoted identifiers are not intuitive when you first see 
them. I'd entertain the idea of switching to brackets, e.g.

  select * from [HR].[Employees] where [name] = 'Ted'
                
> Difference between single and double quotes not clear and error messages are 
> opaque
> -----------------------------------------------------------------------------------
>
>                 Key: DRILL-197
>                 URL: https://issues.apache.org/jira/browse/DRILL-197
>             Project: Apache Drill
>          Issue Type: Bug
>            Reporter: Ted Dunning
>
> The following query fails:
> {code}
> select _MAP["N_REGIONKEY"] 
> from "nation.parquet"
> {code}
> but the following very similar query succeeds:
> {code}
> select _MAP['N_REGIONKEY'] 
> from "nation.parquet"
> {code}
> The difference is in the use of single or double quotes for the index of 
> {{_MAP}}
> I certainly don't know what the difference is here, but it seems important to 
> either resolve or document.
> Conversely, this query also fails, but this time because double quotes *have* 
> to be used.
> {code}
> select _MAP['N_REGIONKEY'] 
> from 'nation.parquet';
> {code}
> This is pretty perverse.

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