Fix column's statistics errors

app/drivers/base.py

@@ -87,6 +87,10 @@ class BaseDriver(ABC):
         """Returns list of database name strings."""
         pass
 
+    def quote_identifier(self, name: str) -> str:
+        """Wrap an identifier in the DB-appropriate quote characters."""
+        return f'"{name}"'
+
     @abstractmethod
     def get_tables(self, database: str) -> list:
         """Returns list of TableInfo for the given database."""

app/drivers/mssql_driver.py

@@ -19,6 +19,9 @@ class MSSQLDriver(BaseDriver):
         super().__init__(config)
         self.db_type = "mssql"
 
+    def quote_identifier(self, name: str) -> str:
+        return f"[{name}]"
+
     def _conn_str(self) -> str:
         host = self.config.get("host", "localhost")
         port = int(self.config.get("port", 1433))

app/drivers/mysql_driver.py

@@ -18,6 +18,9 @@ class MySQLDriver(BaseDriver):
         super().__init__(config)
         self.db_type = "mysql"
 
+    def quote_identifier(self, name: str) -> str:
+        return f"`{name}`"
+
     def _connect_kwargs(self) -> dict:
         kw = {
             "host": self.config.get("host", "localhost"),

app/ui/column_stats_dialog.py

@@ -19,12 +19,13 @@ class _StatsWorker(QThread):
         self._column   = column
 
     def run(self):
-        col  = self._column
-        tbl  = self._table
+        q    = self._driver.quote_identifier
+        col  = q(self._column)
+        tbl  = q(self._table)
         try:
             _, rows, _ = self._driver.execute_query(
-                f'SELECT COUNT(*), COUNT("{col}"), COUNT(DISTINCT "{col}"), '
-                f'MIN("{col}"), MAX("{col}") FROM "{tbl}"'
+                f'SELECT COUNT(*), COUNT({col}), COUNT(DISTINCT {col}), '
+                f'MIN({col}), MAX({col}) FROM {tbl}'
             )
             total, non_null, distinct, min_val, max_val = rows[0]
             null_count = (total or 0) - (non_null or 0)
@@ -35,7 +36,7 @@ class _StatsWorker(QThread):
         avg_val = None
         try:
             _, avg_rows, _ = self._driver.execute_query(
-                f'SELECT AVG("{col}") FROM "{tbl}"'
+                f'SELECT AVG({col}) FROM {tbl}'
             )
             avg_val = avg_rows[0][0]
         except Exception: