vinodkc commented on code in PR #38419:
URL: https://github.com/apache/spark/pull/38419#discussion_r1096439296
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sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/mathExpressions.scala:
##########
@@ -331,6 +332,275 @@ case class RoundCeil(child: Expression, scale: Expression)
copy(child = newLeft, scale = newRight)
}
+
+/**
+ * Truncates a number to the specified number of digits.
+ * @param child
+ * expression to get the number to be truncated.
+ * @param scale
+ * expression to get the number of decimal places to truncate to.
+ */
+case class TruncNumber(child: Expression, scale: Expression)
+ extends BaseBinaryExpression
+ with NullIntolerant {
+
+ override protected def withNewChildrenInternal(
+ newLeft: Expression,
+ newRight: Expression): TruncNumber = copy(child = newLeft, scale =
newRight)
+
+ /**
+ * Returns the [[DataType]] of the result of evaluating this expression. It
is invalid to query
+ * the dataType of an unresolved expression (i.e., when `resolved` == false).
+ */
+ override lazy val dataType: DataType = child.dataType
+
+ /**
+ * This overridden implementation delegates the overloaded TruncNumber.trunc
methods based on
+ * data type of input values
+ */
+ override protected def nullSafeEval(input1: Any, input2: Any): Any = {
+ (dataType, input1) match {
+ // Trunc function accepts a second parameter to truncate the input
number.
+ // If 0, it removes all the decimal values and returns only the integer.
+ // If negative, the number is truncated to the left side of the decimal
point.
+ // Value of decimal places to truncate can range from -ve to +ve
+ // 1) In the case of integral numbers, as there is no decimal part if
the value of decimal
+ // places to truncate is +ve, then we can return that input value
without any
+ // modification as there is no +ve decimal place to be truncated from an
integral number
+ // Truncate the input only if the value of decimal places to truncate is
< 0
+ case (ByteType, input: Byte) if (scaleValue < 0) =>
+ TruncNumber.trunc(input.toLong, scaleValue).toByte
+ case (ShortType, input: Short) if (scaleValue < 0) =>
+ TruncNumber.trunc(input.toLong, scaleValue).shortValue
+ case (IntegerType, input: Int) if (scaleValue < 0) =>
+ TruncNumber.trunc(input.toLong, scaleValue).intValue
+ case (LongType, input: Long) if (scaleValue < 0) =>
+ TruncNumber.trunc(input, scaleValue).longValue
+ // 2) In the case of Float, Double, and Decimal , TruncNumber.trunc
+ // will accept both -ve and +ve values
+ case (FloatType, input: Float) =>
+ TruncNumber.trunc(input, scaleValue).floatValue
+ case (DoubleType, input: Double) =>
+ TruncNumber.trunc(input, scaleValue).doubleValue
+ case (DecimalType.Fixed(p, s), input: Decimal) =>
+ Decimal(TruncNumber.trunc(input.toJavaBigDecimal, scaleValue), p, s)
+ case _ => input1
+ }
+ }
+
+ /**
+ * Returns Java source code that can be compiled to evaluate this expression.
+ * This overridden implementation delegates the overloaded TruncNumber.trunc
methods based on
+ * data type of input values
+ * @param ctx
+ * a [[CodegenContext]]
+ * @param ev
+ * an [[ExprCode]] with unique terms.
+ * @return
+ * an [[ExprCode]] containing the Java source code to generate the given
expression
+ */
+ override protected def doGenCode(ctx: CodegenContext, ev: ExprCode):
ExprCode =
+ defineCodeGen(
+ ctx,
+ ev,
+ (input, _) => {
+ val methodName =
"org.apache.spark.sql.catalyst.expressions.TruncNumber.trunc"
+ // Trunc function accepts a second parameter to truncate the input
number.
+ // If 0, it removes all the decimal values and returns only the
integer.
+ // If negative, the number is truncated to the left side of the
decimal point.
+ // Value of decimal places to truncate can range from -ve to +ve
+ // 1) In the case of integral numbers, as there is no decimal part if
the value of decimal
+ // places to truncate is +ve, then we can return that input value
without any
+ // modification as there is no +ve decimal place to be truncated from
an integral number
+ // Truncate the input only if the value of decimal places to truncate
is < 0
+ dataType match {
+ case ByteType if (scaleValue < 0) =>
+ s"""(byte)($methodName(
+ |(long)$input, $scaleValue))""".stripMargin
+ case ShortType if (scaleValue < 0) =>
+ s"""(short)($methodName(
+ |(long)$input, $scaleValue))""".stripMargin
+ case IntegerType if (scaleValue < 0) =>
+ s"""(int)($methodName(
+ |(long)$input, $scaleValue))""".stripMargin
+ case LongType if (scaleValue < 0) =>
+ s"""($methodName(
+ |$input, $scaleValue))""".stripMargin
+ // 2) In the case of Float, Double, and Decimal , TruncNumber.trunc
+ // will accept both -ve and +ve values
+ case FloatType =>
+ s"""$methodName(
+ |$input, $scaleValue).floatValue()""".stripMargin
+ case DoubleType =>
+ s"""$methodName(
+ |$input, $scaleValue).doubleValue()""".stripMargin
+ case DecimalType.Fixed(p, s) =>
+ s"""Decimal.apply(
+ |$methodName(
+ |${input}.toJavaBigDecimal(), $scaleValue), $p,
$s)""".stripMargin
+ case _ => s"$input"
+ }
+ })
+}
+
+object TruncNumber {
+
+ /**
+ * To truncate whole numbers; byte, short, int, and long types.
+ */
+ def trunc(input: Long, position: Int): Long = {
+ if (position >= 0) {
+ input
+ } else {
+ // Here we truncate the number by the absolute value of the position.
+ // For example, if the input is 123 and the scale is -2, then the result
is 100.
+ val pow = Math.pow(10, Math.abs(position)).toLong
+ (input / pow) * pow
+ }
+ }
+
+ /**
+ * To truncate double and float type.
+ */
+ def trunc(input: Double, position: Int): BigDecimal = {
+ trunc(jm.BigDecimal.valueOf(input), position)
+ }
+
+ /**
+ * To truncate decimal type.
+ */
+ def trunc(input: jm.BigDecimal, position: Int): jm.BigDecimal = {
+ if (input.scale < position) input
+ else {
+ val wholePart = input.toBigInteger
+ position match {
+ case pos if pos >= 0 =>
+ // Here we truncate only the decimal part by the value of the
position.
+ val decimalPart = input.remainder(java.math.BigDecimal.ONE)
+ // If the position is zero OR Decimal part is zero,
+ // we extract the whole part and return it.
+ // For example,
+ // if the input is 123.456 and the scale is 0, the result will be
123.
+ // if the input is 123.000 and the scale is > 0, the result will be
123.
+ val wholePartBD = new jm.BigDecimal(wholePart)
+ if (pos == 0 || jm.BigDecimal.ZERO.compareTo(decimalPart) == 0) {
+ wholePartBD
+ } else {
+ // To avoid overflow during multiplication, we extract the decimal
part from the input,
+ // truncate it and then append it to the whole part.
+ // For example, if the input is 123.456 and the scale is 2, the
result will be 123.45.
+ val pow = jm.BigDecimal.valueOf(Math.pow(10, pos).toLong)
+ val truncated = new
jm.BigDecimal(decimalPart.multiply(pow).toBigInteger).divide(pow)
+ wholePartBD.add(truncated)
+ }
+ case pos if pos < 0 =>
+ // Here we truncate the whole part by the absolute value of the
position.
+ // For example, if the input is 123.456 and the scale is -2, the
result will be 100.
+ val pow = jm.BigInteger.valueOf(Math.pow(10, Math.abs(pos)).toLong)
+ new jm.BigDecimal(wholePart.divide(pow).multiply(pow), 0)
+ }
+ }
+ }
+}
+
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+ usage = """_FUNC_(number[, position]) - Returns the number after truncating
to the specified number of digits.
+ An optional `position` parameter can be specified to truncate digits to
the right of the decimal point.
+ If 0, it removes all the decimal values and returns only the integer.
+ If negative, the number is truncated to the left side of the decimal point.
+ Note that there is an overloaded version of this function to truncate date
values.
+ _FUNC_(date, fmt) - Returns `date` with the time portion of the day
truncated to the unit specified by the format model `fmt`.
+ """,
+ arguments = """
+ Arguments:
+ * number - number to be truncated
+ * position - number of decimal places up to which the given number is to
be truncated
+ Arguments: To truncate date values:
+ * date - date value or valid date string
+ * fmt - the format representing the unit to be truncated to
+ - "YEAR", "YYYY", "YY" - truncate to the first date of the year that
the `date` falls in
+ - "QUARTER" - truncate to the first date of the quarter that the
`date` falls in
+ - "MONTH", "MM", "MON" - truncate to the first date of the month
that the `date` falls in
+ - "WEEK" - truncate to the Monday of the week that the `date` falls
in
+ """,
+ examples = """
+ Examples:
+ > SELECT _FUNC_('2019-08-04', 'week');
+ 2019-07-29
+ > SELECT _FUNC_('2019-08-04', 'quarter');
+ 2019-07-01
+ > SELECT _FUNC_('2009-02-12', 'MM');
+ 2009-02-01
+ > SELECT _FUNC_('2015-10-27', 'YEAR');
+ 2015-01-01
+ > SELECT _FUNC_(-10.11, 0);
+ -10.00
+ > SELECT _FUNC_(10.11, -1);
+ 10.00
+ > SELECT _FUNC_(100.61, 0);
+ 100.00
+ > SELECT _FUNC_(-19087.1560, -3);
+ -19000.0000
+ > SELECT _FUNC_(10876.5489, -1);
+ 10870.0000
+ > SELECT _FUNC_(-7767.1160, 2);
+ -7767.1100
+ > SELECT _FUNC_(17646.6019, 3);
+ 17646.6010
+ """,
+ since = "3.5.0",
+ group = "math_funcs")
+// scalastyle:on line.size.limit
+object TruncExpressionBuilder extends ExpressionBuilder {
+ override def build(funcName: String, expressions: Seq[Expression]):
Expression = {
+ val numArgs = expressions.length
+ if (numArgs < 1) {
+ throw QueryCompilationErrors.invalidFunctionArgumentNumberError(Seq(2),
funcName, numArgs)
+ }
+ expressions(0).dataType match {
+ case ByteType | ShortType | IntegerType | LongType | FloatType |
DoubleType |
+ DecimalType.Fixed(_, _) =>
+ buildTruncNumber(funcName, expressions)
+ case _ => buildTruncDate(funcName, expressions)
+ }
+ }
+
+ private def buildTruncDate(funcName: String, expressions: Seq[Expression]) =
{
+ val numArgs = expressions.length
+ if (numArgs == 2) {
+ TruncDate(expressions(0), expressions(1))
+ } else {
+ throw QueryCompilationErrors.invalidFunctionArgumentNumberError(Seq(2),
funcName, numArgs)
+ }
+ }
+
+ private def buildTruncNumber(funcName: String, expressions: Seq[Expression])
= {
+ val numArgs = expressions.length
+ if (numArgs < 1) {
+ throw QueryCompilationErrors.invalidFunctionArgumentNumberError(Seq(2),
funcName, numArgs)
+ }
+ val position = if (numArgs == 2) {
+ val positionExpr = expressions(1)
+ val scale_value = positionExpr.eval()
+ if (!(positionExpr.foldable && positionExpr.dataType == IntegerType) ||
Review Comment:
Done
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