abhishekagarwal87 commented on code in PR #15713: URL: https://github.com/apache/druid/pull/15713#discussion_r1479381020
########## docs/querying/sql-data-types.md: ########## @@ -146,13 +146,14 @@ affects both storage and querying, and must be set on all Druid service types to and query time. There is some overhead associated with the ability to handle NULLs; see the [segment internals](../design/segments.md#handling-null-values) documentation for more details. -When `druid.generic.useDefaultValueForNull = true` (legacy mode), Druid treats NULLs and empty strings -interchangeably, rather than according to the SQL standard. In this mode Druid SQL only has partial support for NULLs. -For example, the expressions `col IS NULL` and `col = ''` are equivalent, and both evaluate to true if `col` -contains an empty string. Similarly, the expression `COALESCE(col1, col2)` returns `col2` if `col1` is an empty -string. While the `COUNT(*)` aggregator counts all rows, the `COUNT(expr)` aggregator counts the number of rows -where `expr` is neither null nor the empty string. Numeric columns in this mode are not nullable; any null or missing -values are treated as zeroes. This was the default prior to Druid 28.0.0. +When `druid.generic.useDefaultValueForNull = true` (legacy), Druid treats NULLs and empty strings interchangeably, Review Comment: ```suggestion When `druid.generic.useDefaultValueForNull = true` (deprecated legacy mode), Druid treats NULLs and empty strings interchangeably, ``` -- 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]
