feat: add arithmetic function "sqrt" and "factorial" with decimal type (

#674)

extensions/functions_arithmetic_decimal.yaml

@@ -149,6 +149,23 @@ scalar_functions:
         return: |-
           max_precision = max(P1, P2)
           DECIMAL<max_precision, 0>
+  - name: "sqrt"
+    description: Square root of the value. Sqrt of 0 is 0 and sqrt of negative values will raise an error.
+    impls:
+      - args:
+          - name: x
+            value: "DECIMAL<P,S>"
+        return: fp64
+  - name: "factorial"
+    description: >
+      Return the factorial of a given decimal input. Scale should be 0 for factorial decimal input.
+      The factorial of 0! is 1 by convention. Negative inputs will raise an error.
+      Input which cause overflow of result will raise an error.
+    impls:
+      - args:
+          - name: "n"
+            value: "DECIMAL<P,0>"
+        return: "DECIMAL<38,0>"
 aggregate_functions:
   - name: "sum"
     description: Sum a set of values.