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https://issues.apache.org/jira/browse/SPARK-42131?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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jiaan.geng updated SPARK-42131:
-------------------------------
Description:
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}
> 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
> Priority: Major
>
> 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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