Add an example for running queries via vtgate

vitess-grpc/examples/queries.rs

@@ -0,0 +1,40 @@
+use anyhow::Result;
+use vitess_grpc::query::BoundQuery;
+use vitess_grpc::vtgateservice::vitess_client::VitessClient;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // See docker-compose.yml for the details of the vitess deployment
+    let vitess_url = "http://127.0.0.1:15301";
+
+    // Connect to Vitess
+    let mut client = VitessClient::connect(vitess_url)
+        .await
+        .expect("Failed to connect to Vitess");
+
+    // Prepare the query to be executed
+    let exec_request = vitess_grpc::vtgate::ExecuteRequest {
+        query: Some(BoundQuery {
+            sql: "SHOW TABLES FROM commerce".into(),
+            ..Default::default()
+        }),
+        ..Default::default()
+    };
+
+    // Execute the query
+    let res = client.execute(exec_request).await?;
+
+    // Print the results
+    if let Some(result) = res.into_inner().result {
+        let fields = result.fields;
+        println!("fields: {:?}", fields);
+
+        for row in result.rows {
+            println!("row: {:?}", row);
+        }
+    } else {
+        println!("no result");
+    }
+
+    Ok(())
+}