johnImply commented on code in PR #13404: URL: https://github.com/apache/druid/pull/13404#discussion_r1087288626
########## docs/querying/datasource.md: ########## @@ -302,12 +302,15 @@ use join datasources. SQL joins take the form: ``` -<o1> [ INNER | LEFT [OUTER] ] JOIN <o2> ON <condition> +<o1> [ INNER | LEFT [OUTER] | CROSS ] JOIN <o2> ON <condition> ``` -The condition must involve only equalities, but functions are okay, and there can be multiple equalities ANDed together. -Conditions like `t1.x = t2.x`, or `LOWER(t1.x) = t2.x`, or `t1.x = t2.x AND t1.y = t2.y` can all be handled. Conditions -like `t1.x <> t2.x` cannot currently be handled. +JOIN conditions have the following requirements: +- You can only use equality statements in JOIN conditions. For example: `t1.x = t2.x` +- You can use functions on the operands in JOIN conditions. For example: `LOWER(t1.x) = t2.x` +- You can apply multiple equality conditions using the AND operator. For example: `t1.x = t2.x AND t1.y = t2.y` +- Inequality conditions are unsupported. For example: `t1.x <> t2.x` +- Conditions are optional for CROSS JOIN. Review Comment: I don't think CROSS JOIN will accept join conditions ... -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
