[jira] [Resolved] (SPARK-42131) Extract the function that construct the select statement for JDBC dialect.

["Wenchen Fan (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-42131?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Wenchen Fan resolved SPARK-42131.
---------------------------------
    Fix Version/s: 3.5.0
       Resolution: Fixed

Issue resolved by pull request 39667
[https://github.com/apache/spark/pull/39667]

> Extract the function that construct the select statement for JDBC dialect.
> --------------------------------------------------------------------------
>
>                 Key: SPARK-42131
>                 URL: https://issues.apache.org/jira/browse/SPARK-42131
>             Project: Spark
>          Issue Type: Sub-task
>          Components: SQL
>    Affects Versions: 3.4.0
>            Reporter: jiaan.geng
>            Assignee: jiaan.geng
>            Priority: Major
>             Fix For: 3.5.0
>
>
> Currently, JDBCRDD uses fixed format for SELECT statement.
> {code:java}
> val sqlText = options.prepareQuery +
>       s"SELECT $columnList FROM ${options.tableOrQuery} $myTableSampleClause" +
>       s" $myWhereClause $getGroupByClause $getOrderByClause $myLimitClause $myOffsetClause"
> {code}
> But some databases have different syntax that uses different keyword or sort. For example, MS SQL Server uses keyword TOP to describe LIMIT clause or Top N.
> The LIMIT clause of MS SQL Server.
> {code:java}
> SELECT TOP(1) Model, Color, Price  
>       FROM dbo.Cars  
>       WHERE Color = 'blue'
> {code}
> The Top N of MS SQL Server.
> {code:java}
> SELECT TOP(1) Model, Color, Price  
> FROM dbo.Cars  
> WHERE Color = 'blue'  
> ORDER BY Price ASC
> {code}



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