There have been a few customer issues with long-running correlated queries that could have been decorrelated with the following decorrelation rule: for correlated Select and Join operators that have a filter that sets an outer column equal to a non-outer column, replace all references to the outer column with the equivalent non-outer column. This rule should be valid even for left joins, since any right row for which the replacement does not hold will not become part of the output.

Jira issue: CRDB-20024