Struct Query

pub struct Query { /* private fields */ }

Implementations

impl Query

pub fn sql_display(&self) -> &impl Display

Display SQL query as string.

pub fn bind(self, value: impl Bind) -> Self

Binds value to the next ? in the query.

The value, which must either implement Serialize or be an Identifier, will be appropriately escaped.

All possible errors will be returned as Error::InvalidParams during query execution (execute(), fetch() etc).

WARNING: This means that the query must not have any extra ?, even if they are in a string literal! Use ?? to have plain ? in query.

pub async fn execute(self) -> Result<()>

Executes the query.

pub fn fetch<T: Row>(self) -> Result<RowCursor<T>>

Executes the query, returning a RowCursor to obtain results.

Example

#[derive(clickhouse::Row, serde::Deserialize)]
struct MyRow<'a> {
    no: u32,
    name: &'a str,
}

let mut cursor = clickhouse::Client::default()
    .query("SELECT ?fields FROM some WHERE no BETWEEN 0 AND 1")
    .fetch::<MyRow<'_>>()?;

while let Some(MyRow { name, no }) = cursor.next().await? {
    println!("{name}: {no}");
}

pub async fn fetch_one<T>(self) -> Result<T>

where T: Row + for<'b> Deserialize<'b>,

Executes the query and returns just a single row.

Note that T must be owned.

pub async fn fetch_optional<T>(self) -> Result<Option<T>>

where T: Row + for<'b> Deserialize<'b>,

Executes the query and returns at most one row.

Note that T must be owned.

pub async fn fetch_all<T>(self) -> Result<Vec<T>>

where T: Row + for<'b> Deserialize<'b>,

Executes the query and returns all the generated results, collected into a Vec.

Note that T must be owned.

pub fn fetch_bytes(self, format: impl Into<String>) -> Result<BytesCursor>

Executes the query, returning a BytesCursor to obtain results as raw bytes containing data in the provided format.

pub fn with_option( self, name: impl Into<String>, value: impl Into<String>, ) -> Self

Similar to Client::with_option, but for this particular query only.

pub fn param(self, name: &str, value: impl Serialize) -> Self

Specify server side parameter for query.

In queries you can reference params as {name: type} e.g. {val: Int32}.

Trait Implementations

impl Clone for Query

fn clone(&self) -> Query

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.