Macro sql 

macro_rules! sql {
    ($template:literal $(,)?) => { ... };
    ($template:literal, $($arg:expr),+ $(,)?) => { ... };
    (@unit $_arg:expr) => { ... };
}

Builds a Sql fragment from a static template and SQL arguments.

The template uses {} placeholders for SQL arguments and {{/}} to escape literal braces. Argument count is verified at compile time.