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https://issues.apache.org/jira/browse/CALCITE-1917?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16911072#comment-16911072
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ShuMing Li commented on CALCITE-1917:
-------------------------------------

Has this issue already resolved?  I find Calcite already support such tests in 
`SqlToRelConverterTest.java`:
{code:java}
@Test public void testJoinTemporalTableOnColumnReference() {
  final String sql = "select stream *\n"
      + "from orders\n"
      + "join products_temporal for system_time as of orders.rowtime\n"
      + "on orders.productid = products_temporal.productid";
  sql(sql).ok();
}
{code}

> Support column reference in "FOR SYSTEM_TIME AS OF"
> ---------------------------------------------------
>
>                 Key: CALCITE-1917
>                 URL: https://issues.apache.org/jira/browse/CALCITE-1917
>             Project: Calcite
>          Issue Type: New Feature
>            Reporter: Jark Wu
>            Priority: Major
>
> As discussed in mailing list[1], the standard says QSTPS can’t contain a 
> column reference. So when joining the Orders to the Products table for the 
> price as of the time the order was placed is impossible using "FOR 
> SYSTEM_TIME AS OF". But can be expressed using a subquery, such as:
> {code}
>  SELECT  *
>     FROM Orders AS o
>     JOIN LATERAL (SELECT * FROM ProductPrices WHERE sysStart <= O.orderTime 
> AND sysEnd > O.orderTime) AS P
>       ON o.productId = p.productId
> {code}
> But subquery is too complex for users. We know that the standard says it 
> can’t contain a column reference. We initialize this discuss as we would like 
> to "extend" the standard to simplify such query:
> {code}
>  SELECT  *
>     FROM Orders AS o
>     JOIN LATERAL ProductPrices FOR SYSTEM_TIME AS OF O.orderTime AS P
>       ON o.productId = p.productId
> {code}
> [1] 
> https://lists.apache.org/thread.html/f877f356a8365bf74ea7d8e4a171224104d653cf73861afb2901a58f@%3Cdev.calcite.apache.org%3E



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