tanclary commented on code in PR #3234:
URL: https://github.com/apache/calcite/pull/3234#discussion_r1254726840
##########
babel/src/test/resources/sql/big-query.iq:
##########
@@ -600,6 +600,44 @@ FROM t;
!ok
!}
+#####################################################################
+# SAFE_MULTIPLY
+#
+# SAFE_MULTIPLY(value1, value2)
+#
+# Equivalent to the mulitply operator (*), but returns NULL if
overflow/underflow occurs.
+SELECT SAFE_MULTIPLY(5, 4) as result;
++--------+
+| result |
++--------+
+| 20 |
++--------+
+(1 row)
+
+!ok
+
+#Overflow occurs if result is greater than 2^63 - 1
+SELECT SAFE_MULTIPLY(9223372036854775807, 2) as overflow_result;
++-----------------+
+| overflow_result |
++-----------------+
+| |
++-----------------+
+(1 row)
+
+!ok
+
+#Underflow occurs if result is less than -2^63
+SELECT SAFE_MULTIPLY(-9223372036854775806, 3) as underflow_result;
++------------------+
+| underflow_result |
++------------------+
+| |
++------------------+
+(1 row)
+
+!ok
+
Review Comment:
Done.
##########
core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java:
##########
@@ -1524,6 +1524,91 @@ public static int multiply(int b0, int b1) {
throw notArithmetic("*", b0, b1);
}
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to long values. */
+ public static @Nullable Long safeMultiply(long b0, long b1) {
+ try {
+ return Math.multiplyExact(b0, b1);
+ } catch (ArithmeticException e) {
+ return null;
+ }
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to long and BigDecimal
values. */
+ public static @Nullable BigDecimal safeMultiply(long b0, BigDecimal b1) {
+ BigDecimal ans = BigDecimal.valueOf(b0).multiply(b1);
+ return safeDecimal(ans) ? ans : null;
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to BigDecimal and long
values. */
+ public static @Nullable BigDecimal safeMultiply(BigDecimal b0, long b1) {
+ BigDecimal ans = b0.multiply(BigDecimal.valueOf(b1));
+ return safeDecimal(ans) ? ans : null;
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to BigDecimal values. */
+ public static @Nullable BigDecimal safeMultiply(BigDecimal b0, BigDecimal
b1) {
+ BigDecimal ans = b0.multiply(b1);
+ return safeDecimal(ans) ? ans : null;
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to double and long
values. */
+ public static @Nullable Double safeMultiply(double b0, long b1) {
+ double ans = b0 * b1;
+ boolean isInfinite = Double.isInfinite(b0);
+ return safeDecimal(ans) || isInfinite ? ans : null;
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to long and double
values. */
+ public static @Nullable Double safeMultiply(long b0, double b1) {
+ double ans = b0 * b1;
+ boolean isInfinite = Double.isInfinite(b1);
+ return safeDecimal(ans) || isInfinite ? ans : null;
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to double and BigDecimal
values. */
+ public static @Nullable Double safeMultiply(double b0, BigDecimal b1) {
+ double ans = b0 * b1.doubleValue();
+ boolean isInfinite = Double.isInfinite(b0);
+ return safeDecimal(ans) || isInfinite ? ans : null;
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to BigDecimal and double
values. */
+ public static @Nullable Double safeMultiply(BigDecimal b0, double b1) {
+ double ans = b0.doubleValue() * b1;
+ boolean isInfinite = Double.isInfinite(b1);
+ return safeDecimal(ans) || isInfinite ? ans : null;
+ }
+
+ /** SQL <code>SAFE_MULTIPLY</code> function applied to double values. */
+ public static @Nullable Double safeMultiply(double b0, double b1) {
+ double ans = b0 * b1;
+ boolean isInfinite = Double.isInfinite(b0) || Double.isInfinite(b1);
+ return safeDecimal(ans) || isInfinite ? ans : null;
+ }
+
+ /** Helper for the safe arithmetic functions to determine
+ * overflow for a BigDecimal value. According to BigQuery, BigDecimal
+ * overflow occurs if the precision is greater than 76 or the precision
+ * is greater than 38. */
+ private static boolean safeDecimal(BigDecimal b) {
+ return b.scale() <= 38 && b.precision() <= 76;
+ }
+
+ /** Helper for the safe arithmetic functions to determine
+ * overflow for a double. */
+ private static boolean safeDecimal(double d) {
Review Comment:
Good call. Done.
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