diff --git a/singer_sdk/connectors/sql.py b/singer_sdk/connectors/sql.py
index b00b47252a..073f7e62db 100644
--- a/singer_sdk/connectors/sql.py
+++ b/singer_sdk/connectors/sql.py
@@ -839,7 +839,7 @@ def get_object_names(
             view_names = []
         return [(t, False) for t in table_names] + [(v, True) for v in view_names]
 
-    def discover_catalog_entry_sql_datatype(  # noqa: PLR6301
+    def _sa_type_to_str(  # noqa: PLR6301
         self,
         data_type: sa.types.TypeEngine,
     ) -> str:
@@ -908,6 +908,7 @@ def discover_catalog_entry(
 
         # Initialize columns list
         table_schema = th.PropertiesList()
+        datatypes = {}
         for column_def in inspected.get_columns(table_name, schema=schema_name):
             column_name = column_def["name"]
             is_nullable = column_def.get("nullable", False)
@@ -920,13 +921,9 @@ def discover_catalog_entry(
                     required=column_name in key_properties if key_properties else False,
                 ),
             )
-        schema = table_schema.to_dict()
+            datatypes[column_def["name"]] = self._sa_type_to_str(column_def["type"])
 
-        sql_datatypes = {}
-        for column_def in inspected.get_columns(table_name, schema=schema_name):
-            sql_datatypes[str(column_def["name"])] = (
-                self.discover_catalog_entry_sql_datatype(column_def["type"])
-            )
+        schema = table_schema.to_dict()
 
         # Initialize available replication methods
         addl_replication_methods: list[str] = [""]  # By default an empty list.
@@ -952,7 +949,7 @@ def discover_catalog_entry(
                 replication_method=replication_method,
                 key_properties=key_properties,
                 valid_replication_keys=None,  # Must be defined by user
-                sql_datatypes=sql_datatypes,
+                sql_datatypes=datatypes,
             ),
             database=None,  # Expects single-database context
             row_count=None,