fix: handle DESCRIBE SELECT

mysql_mimic/session.py

@@ -393,6 +393,9 @@ async def _show(self, expression: exp.Show) -> AllowedResult:
     async def _describe_middleware(self, q: Query) -> AllowedResult:
         """Intercept DESCRIBE statements"""
         if isinstance(q.expression, exp.Describe):
+            if isinstance(q.expression.this, exp.Select):
+                # Mysql parse treats EXPLAIN SELECT as a DESCRIBE SELECT statement
+                return await q.next()
             name = q.expression.this.name
             show = self.dialect().parse(f"SHOW COLUMNS FROM {name}")[0]
             return await self._show(show) if isinstance(show, exp.Show) else None

tests/conftest.py

@@ -77,6 +77,12 @@ async def query(
             self.waiting.set()
             await self.pause.wait()
             self.waiting.clear()
+
+        if isinstance(expression, exp.Describe):
+            assert isinstance(expression.this, exp.Select)
+            sql = expression.this.sql()
+            return [(sql,)], ["sql"]
+
         assert isinstance(expression, exp.Select)
         self.last_query_attrs = attrs
         if self.echo:

tests/test_query.py

@@ -730,6 +730,14 @@ async def test_query_attributes(
                 },
             ],
         ),
+        (
+            "describe SELECT b FROM a",
+            [
+                {
+                    "sql": "SELECT b FROM a",
+                },
+            ],
+        ),
         (
             "show tables from information_schema like 'k%'",
             [