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SQL "order by" query returns wrong order for +0.0 and -0.0 #3825
Description
Describe the bug
Spark returns +0.0 first
Comet returns -0.0 first
Steps to reproduce
test("negative zero order by") {
withTable("t1") {
Seq(0.0f, -0.0f).toDF("a").write.saveAsTable("t1")
val df = sql("SELECT * FROM t1 ORDER BY a")
checkSparkAnswerAndOperator(df)
}
}Expected behavior
No response
Additional context
No response
Activity
andygrove commentedon Mar 28, 2026
This is documented in the compatibility guide already, and there is a config that can be enabled to fallback to Spark for this case.
https://datafusion.apache.org/comet/user-guide/latest/compatibility.html#floating-point-number-comparison
kazuyukitanimura commentedon Mar 30, 2026
The main issue is that many tests sort results and fails due to this incompatibility issue, so we have to treat the tests differently.
May not be a problem for end users, but for development purpose, we should fix this.