use of com.facebook.presto.common.function.OperatorType.DIVIDE in project presto by prestodb.
the class DecimalOperators method decimalDivideOperator.
private static SqlScalarFunction decimalDivideOperator() {
TypeSignature decimalLeftSignature = parseTypeSignature("decimal(a_precision, a_scale)", ImmutableSet.of("a_precision", "a_scale"));
TypeSignature decimalRightSignature = parseTypeSignature("decimal(b_precision, b_scale)", ImmutableSet.of("b_precision", "b_scale"));
TypeSignature decimalResultSignature = parseTypeSignature("decimal(r_precision, r_scale)", ImmutableSet.of("r_precision", "r_scale"));
// we extend target precision by b_scale. This is upper bound on how much division result will grow.
// pessimistic case is a / 0.0000001
// if scale of divisor is greater than scale of dividend we extend scale further as we
// want result scale to be maximum of scales of divisor and dividend.
Signature signature = SignatureBuilder.builder().kind(SCALAR).operatorType(DIVIDE).longVariableConstraints(longVariableExpression("r_precision", "min(38, a_precision + b_scale + max(b_scale - a_scale, 0))"), longVariableExpression("r_scale", "max(a_scale, b_scale)")).argumentTypes(decimalLeftSignature, decimalRightSignature).returnType(decimalResultSignature).build();
return SqlScalarFunction.builder(DecimalOperators.class, DIVIDE).signature(signature).deterministic(true).choice(choice -> choice.implementation(methodsGroup -> methodsGroup.methods("divideShortShortShort", "divideShortLongShort", "divideLongShortShort", "divideShortShortLong", "divideLongLongLong", "divideShortLongLong", "divideLongShortLong").withExtraParameters(DecimalOperators::divideRescaleFactor))).build();
}
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