Fix issue with colalign and empty resultset

changelog.md

@@ -12,6 +12,7 @@ Features
 Bug Fixes
 --------
 * Better respect case when `keyword_casing` is `auto`.
+* Fix error when selecting from an empty table.
 * Let favorite queries contain special commands.
 * Render binary values more consistently as hex literals.
 

mycli/main.py

@@ -1422,8 +1422,11 @@ def get_col_type(col) -> type:
                     col_type = FIELD_TYPES.get(col[1], str)
                     return col_type if type(col_type) is type else str
 
-                column_types = [get_col_type(tup) for tup in cur.description]
-                colalign = [numeric_alignment if x in (int, float, Decimal) else 'left' for x in column_types]
+                if cur.rowcount > 0:
+                    column_types = [get_col_type(tup) for tup in cur.description]
+                    colalign = [numeric_alignment if x in (int, float, Decimal) else 'left' for x in column_types]
+                else:
+                    column_types, colalign = [], []
 
             if max_width is not None and isinstance(cur, Cursor):
                 cur = list(cur)

test/test_main.py

@@ -40,6 +40,20 @@
 ]
 
 
+@dbtest
+def test_select_from_empty_table(executor):
+    run(executor, """create table t1(id int)""")
+    sql = "select * from t1"
+    runner = CliRunner()
+    result = runner.invoke(cli, args=CLI_ARGS + ["-t"], input=sql)
+    expected = dedent("""\
+        +----+
+        | id |
+        +----+
+        +----+""")
+    assert expected in result.output
+
+
 def test_is_valid_connection_scheme_valid(executor, capsys):
     is_valid, scheme = is_valid_connection_scheme("mysql://test@localhost:3306/dev")
     assert is_valid