docs: add a server-side params example (#288)

Author: slvrtrn

examples/README.md

@@ -14,6 +14,7 @@ If something is missing, or you found a mistake in one of these examples, please
 - [async_insert.rs](async_insert.rs) - using the server-side batching via the [asynchronous inserts](https://clickhouse.com/docs/en/optimize/asynchronous-inserts) ClickHouse feature
 - [clickhouse_cloud.rs](clickhouse_cloud.rs) - using the client with ClickHouse Cloud, highlighting a few relevant settings (`wait_end_of_query`, `select_sequential_consistency`). Cargo features: requires `rustls-tls`; the code also works with `native-tls`.
 - [clickhouse_settings.rs](clickhouse_settings.rs) - applying various ClickHouse settings on the query level
+- [server_side_params.rs](server_side_params.rs) - parametrized queries with server-side parameters
 
 ### Data types
 

examples/server_side_params.rs

@@ -0,0 +1,31 @@
+use clickhouse::{error::Result, Client};
+
+/// An example of using server-side query parameters.
+///
+/// In most cases, this is the preferred method over the client-side binding
+/// via [`clickhouse::query::Query::bind`].
+///
+/// See also: https://clickhouse.com/docs/sql-reference/syntax#defining-and-using-query-parameters
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    let client = Client::default().with_url("http://localhost:8123");
+
+    let result = client
+        .query(
+            "
+                SELECT {tbl:Identifier}.{col:Identifier}
+                FROM {db:Identifier}.{tbl:Identifier}
+                WHERE {col:Identifier} < {val:UInt64}
+            ",
+        )
+        .param("db", "system")
+        .param("tbl", "numbers")
+        .param("col", "number")
+        .param("val", 3u64)
+        .fetch_all::<u64>()
+        .await?;
+
+    println!("Parametrized query output: {:?}", result);
+    Ok(())
+}