Github user viirya commented on a diff in the pull request:
https://github.com/apache/spark/pull/20023#discussion_r158238981
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/types/DecimalType.scala ---
@@ -136,10 +137,54 @@ object DecimalType extends AbstractDataType {
case DoubleType => DoubleDecimal
}
+ private[sql] def forLiteral(literal: Literal): DecimalType =
literal.value match {
+ case v: Short => fromBigDecimal(BigDecimal(v))
+ case v: Int => fromBigDecimal(BigDecimal(v))
+ case v: Long => fromBigDecimal(BigDecimal(v))
+ case _ => forType(literal.dataType)
+ }
+
+ private[sql] def fromBigDecimal(d: BigDecimal): DecimalType = {
+ DecimalType(Math.max(d.precision, d.scale), d.scale)
+ }
+
private[sql] def bounded(precision: Int, scale: Int): DecimalType = {
DecimalType(min(precision, MAX_PRECISION), min(scale, MAX_SCALE))
}
+ // scalastyle:off line.size.limit
+ /**
+ * Decimal implementation is based on Hive's one, which is itself
inspired to SQLServer's one.
+ * In particular, when a result precision is greater than {@link
#MAX_PRECISION}, the
+ * corresponding scale is reduced to prevent the integral part of a
result from being truncated.
+ *
+ * For further reference, please see
+ *
https://blogs.msdn.microsoft.com/sqlprogrammability/2006/03/29/multiplication-and-division-with-numerics/.
+ *
+ * @param precision
+ * @param scale
+ * @return
+ */
+ // scalastyle:on line.size.limit
+ private[sql] def adjustPrecisionScale(precision: Int, scale: Int):
DecimalType = {
+ // Assumptions:
+ // precision >= scale
+ // scale >= 0
+ if (precision <= MAX_PRECISION) {
+ // Adjustment only needed when we exceed max precision
+ DecimalType(precision, scale)
+ } else {
+ // Precision/scale exceed maximum precision. Result must be adjusted
to MAX_PRECISION.
+ val intDigits = precision - scale
+ // If original scale less than MINIMUM_ADJUSTED_SCALE, use original
scale value; otherwise
+ // preserve at least MINIMUM_ADJUSTED_SCALE fractional digits
+ val minScaleValue = Math.min(scale, MINIMUM_ADJUSTED_SCALE)
--- End diff --
> We can't have a scale lower that that...
Don't you get a scale lower than `MINIMUM_ADJUSTED_SCALE` by
`Math.min(scale, MINIMUM_ADJUSTED_SCALE)`?
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
