[jira] [Commented] (CALCITE-3191) In JDBC adapter for MySQL, implement Values by generating SELECT without FROM

["Julian Hyde (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-3191?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16884182#comment-16884182 ] 

Julian Hyde commented on CALCITE-3191:
--------------------------------------

This is related to previous work implementing {{Values}} for Oracle by generating a call to Oracle's {{DUAL}} table.

Also, improve the logic by which we add "AS t" to a sub-query in the FROM clause. The following {{SqlDialect}} methods are relevant to this fix:
 * {{boolean requiresAliasForFromItems()}} // returns true for MySQL, Postgres
 * {{boolean supportsAliasedValues()}} // returns false on MySQL, true otherwise
 * {{List<String> getSingleRowTableName()}} // returns  ["DUAL"] for Oracle, null otherwise
 * {{boolean hasImplicitTableAlias()}}

 

> In JDBC adapter for MySQL, implement Values by generating SELECT without FROM
> -----------------------------------------------------------------------------
>
>                 Key: CALCITE-3191
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3191
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Julian Hyde
>            Priority: Major
>
> In JDBC adapter, generate implement {{Values}} relational operator by generating {{SELECT}} without a {{FROM}} clause. (For most dialects we generate {{VALUES}}, but MySQL does not support VALUES in a query.)



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