1 files changed, 18 insertions, 21 deletions
diff --git a/sqlglot/dialects/tableau.py b/sqlglot/dialects/tableau.py
index 51e685b..d5fba17 100644
--- a/sqlglot/dialects/tableau.py
+++ b/sqlglot/dialects/tableau.py
@@ -4,41 +4,38 @@ from sqlglot import exp, generator, parser, transforms
 from sqlglot.dialects.dialect import Dialect
 
 
-def _if_sql(self, expression):
-    return f"IF {self.sql(expression, 'this')} THEN {self.sql(expression, 'true')} ELSE {self.sql(expression, 'false')} END"
-
-
-def _coalesce_sql(self, expression):
-    return f"IFNULL({self.sql(expression, 'this')}, {self.expressions(expression)})"
-
-
-def _count_sql(self, expression):
-    this = expression.this
-    if isinstance(this, exp.Distinct):
-        return f"COUNTD({self.expressions(this, flat=True)})"
-    return f"COUNT({self.sql(expression, 'this')})"
-
-
 class Tableau(Dialect):
     class Generator(generator.Generator):
         JOIN_HINTS = False
         TABLE_HINTS = False
 
         TRANSFORMS = {
-            **generator.Generator.TRANSFORMS,  # type: ignore
-            exp.If: _if_sql,
-            exp.Coalesce: _coalesce_sql,
-            exp.Count: _count_sql,
+            **generator.Generator.TRANSFORMS,
             exp.Select: transforms.preprocess([transforms.eliminate_distinct_on]),
         }
 
         PROPERTIES_LOCATION = {
-            **generator.Generator.PROPERTIES_LOCATION,  # type: ignore
+            **generator.Generator.PROPERTIES_LOCATION,
             exp.VolatileProperty: exp.Properties.Location.UNSUPPORTED,
         }
 
+        def if_sql(self, expression: exp.If) -> str:
+            this = self.sql(expression, "this")
+            true = self.sql(expression, "true")
+            false = self.sql(expression, "false")
+            return f"IF {this} THEN {true} ELSE {false} END"
+
+        def coalesce_sql(self, expression: exp.Coalesce) -> str:
+            return f"IFNULL({self.sql(expression, 'this')}, {self.expressions(expression)})"
+
+        def count_sql(self, expression: exp.Count) -> str:
+            this = expression.this
+            if isinstance(this, exp.Distinct):
+                return f"COUNTD({self.expressions(this, flat=True)})"
+            return f"COUNT({self.sql(expression, 'this')})"
+
     class Parser(parser.Parser):
         FUNCTIONS = {
-            **parser.Parser.FUNCTIONS,  # type: ignore
+            **parser.Parser.FUNCTIONS,
             "COUNTD": lambda args: exp.Count(this=exp.Distinct(expressions=args)),
         }