fix: fix mssql syntax in subqueries

Author: albersonmiranda

ibis/backends/sql/compilers/mssql.py

@@ -61,6 +61,20 @@ def rewrite_rows_range_order_by_window(_, **kwargs):
     return _.copy(order_by=(_.func.arg,))
 
 
+from ibis.expr.datatypes import dt
+from ibis.expr.operations import IfElse
+
+# wrap any boolean-valued SELECT column in IIF(..) CAST BIT (Gil tip)
+@replace(p.Select)
+def cast_boolean_in_select(_, **kwargs):
+    new_selections: dict[str, Any] = {}
+    for name, expr in _.selections.items():
+        if expr.dtype.is_boolean():
+            new_selections[name] = IfElse(expr, 1, 0).cast(dt.boolean)
+        else:
+            new_selections[name] = expr
+    return _.copy(selections=new_selections)
+
 class MSSQLCompiler(SQLGlotCompiler):
     __slots__ = ()
 
@@ -69,6 +83,7 @@ class MSSQLCompiler(SQLGlotCompiler):
     dialect = MSSQL
     type_mapper = MSSQLType
     rewrites = (
+        cast_boolean_in_select,
         exclude_unsupported_window_frame_from_ops,
         exclude_unsupported_window_frame_from_row_number,
         exclude_unsupported_window_frame_from_rank,
@@ -553,5 +568,13 @@ def visit_RPad(self, op, *, arg, length, pad):
             ),
         )
 
+    def visit_IfElse(self, op, *, bool_expr, true_expr, false_null_expr):
+        iif_expr = super().visit_IfElse(
+            op,
+            bool_expr=bool_expr,
+            true_expr=true_expr,
+            false_null_expr=false_null_expr,
+        )
+        return self.cast(iif_expr, dt.boolean)
 
 compiler = MSSQLCompiler()