How to Use sqlx for Compile-Time Checked SQL Queries

Use sqlx::query! or sqlx::query_as! macros to compile-time check SQL syntax and column types against your database schema.

use sqlx::{query, PgPool};

#[tokio::main]
async fn main() {
    let pool = PgPool::connect("postgres://localhost").await.unwrap();
    let name: String = sqlx::query_scalar("SELECT name FROM users WHERE id = 1")
        .fetch_one(&pool)
        .await
        .unwrap();
}

Run cargo sqlx prepare to validate queries against your actual database schema during development.

sqlx checks your SQL code while your program compiles, not when it runs. It ensures your database columns match your Rust types and that your SQL syntax is correct before you ever start the app. Think of it like a spellchecker that catches database typos before you ship your software.