TO_NUMBER/TO_DECIMAL/TO_NUMERIC without precision and scale

core/src/main/scala/com/databricks/labs/remorph/parsers/snowflake/rules/SnowflakeCallMapper.scala

@@ -149,7 +149,7 @@ class SnowflakeCallMapper extends ir.CallMapper with ir.IRHelpers {
   private def toNumber(args: Seq[ir.Expression]): ir.Expression = {
     val getArg: Int => Option[ir.Expression] = args.lift
     if (args.size < 2) {
-      throw TranspileException(ir.WrongNumberOfArguments("TO_NUMBER", args.size, "at least 2"))
+      ir.Cast(args.head, ir.DecimalType(38, 0))
     } else if (args.size == 2) {
       ir.ToNumber(args.head, args(1))
     } else {

core/src/test/scala/com/databricks/labs/remorph/transpilers/SnowflakeToDatabricksTranspilerTest.scala

@@ -6,6 +6,26 @@ class SnowflakeToDatabricksTranspilerTest extends AnyWordSpec with TranspilerTes
 
   protected val transpiler = new SnowflakeToDatabricksTranspiler
 
+  "transpile TO_NUMBER and TO_DECIMAL" should {
+    "transpile TO_NUMBER" in {
+      "select TO_NUMBER(EXPR) from test_tbl;" transpilesTo
+        """SELECT CAST(EXPR AS DECIMAL(38, 0)) FROM test_tbl
+          |  ;""".stripMargin
+    }
+
+    "transpile TO_NUMBER with precision and scale" in {
+      "select TO_NUMBER(EXPR,38,0) from test_tbl;" transpilesTo
+        """SELECT CAST(EXPR AS DECIMAL(38, 0)) FROM test_tbl
+          |  ;""".stripMargin
+    }
+
+    "transpile TO_DECIMAL" in {
+      "select TO_DECIMAL(EXPR) from test_tbl;" transpilesTo
+        """SELECT CAST(EXPR AS DECIMAL(38, 0)) FROM test_tbl
+          |  ;""".stripMargin
+    }
+  }
+
   "snowsql commands" should {
 
     "transpile BANG with semicolon" in {

src/databricks/labs/remorph/snow/databricks.py

@@ -270,6 +270,10 @@ def _to_number(self, expression: local_expression.ToNumber):
         if precision:
             return f"CAST({func_expr} AS DECIMAL({precision}, {scale}))"
         return func_expr
+    if not precision:
+        precision = 38
+    if not scale:
+        scale = 0
     if not expression.expression and not precision:
         exception_msg = f"""Error Parsing expression {expression}:
                          * `format`: is required in Databricks [mandatory]

tests/resources/functional/snowflake/functions/conversion/test_to_number/test_to_number_9.sql

@@ -0,0 +1,6 @@
+
+-- snowflake sql:
+select TO_NUMBER(EXPR) from test_tbl;
+
+-- databricks sql:
+SELECT CAST(EXPR AS DECIMAL(38, 0)) FROM test_tbl;