yaooqinn commented on a change in pull request #26702: [SPARK-30070][SQL]
Support ANSI datetimes predicate - overlaps
URL: https://github.com/apache/spark/pull/26702#discussion_r355343902
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File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala
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@@ -2165,3 +2165,75 @@ case class SubtractDates(left: Expression, right:
Expression)
}
}
+/**
+ * The operator `OVERLAPS` determines whether or not two chronological periods
overlap in time. A
+ * chronological period is specified by a pair of datetimes (starting and
ending) or as a
+ * starting datetime and an interval(resolved by analyzer to datetimes pairs
early).
+ *
+ * If the length of the period is greater than 0, then the period consists of
all points of time
+ * greater than or equal to the lower endpoint, and less than the upper
endpoint,
+ * a.k.a [lower, upper).
+ *
+ * If the length of the period is equal to 0, then the period consists of a
single point in time,
+ * the lower endpoint, a.k.a [lower, lower].
+ *
+ * Two periods overlap if they have at least one point in common.
+ *
+ */
+case class DateTimeOverlaps private (
+ leftStart: Expression,
+ leftEnd: Expression,
+ rightStart: Expression,
+ rightEnd: Expression,
+ child: Expression)
+ extends RuntimeReplaceable {
+
+ def this(leftStart: Expression,
+ leftEnd: Expression,
+ rightStart: Expression,
+ rightEnd: Expression) =
+ this(leftStart, leftEnd, rightStart, rightEnd, {
+ val left = Seq(leftStart, leftEnd)
+ val right = Seq(rightStart, rightEnd)
+ If(And(EqualTo(leftStart, leftEnd), EqualTo(rightStart, rightEnd)), /**
both periods are 0 */
+ EqualTo(leftStart, rightStart),
+ If(EqualTo(leftStart, leftEnd), /** left period is 0, ll ∈ [rl, ru) */
+ And(GreaterThanOrEqual(leftStart, Least(right)), LessThan(leftStart,
Greatest(right))),
+ If(EqualTo(rightStart, rightEnd), /** right period is 0, rl ∈ [ll,
lu) */
+ And(GreaterThanOrEqual(rightStart, Least(left)),
LessThan(rightStart, Greatest(left))),
+ {
+ val timePoints = Seq(leftStart, leftEnd, rightStart, rightEnd)
+ val leftPeriod = If(GreaterThan(leftStart, leftEnd),
+ Subtract(leftStart, leftEnd), Subtract(leftEnd, leftStart))
+ val rightPeriod = If(GreaterThan(rightStart, rightEnd),
+ Subtract(rightStart, rightEnd), Subtract(rightEnd, rightStart))
+ LessThan(Subtract(Greatest(timePoints), Least(timePoints)),
+ Add(leftPeriod, rightPeriod))
Review comment:
looks nice
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