fix(sqlite): argument bind for sqlite is 1-indexed

fixes #467

sqlx-core/src/sqlite/arguments.rs

@@ -55,7 +55,7 @@ impl SqliteArguments<'_> {
         let mut arg_i = 0;
         for handle in &statement.handles {
             let cnt = handle.bind_parameter_count();
-            for param_i in 0..cnt {
+            for param_i in 1..=cnt {
                 // figure out the index of this bind parameter into our argument tuple
                 let n: usize = if let Some(name) = handle.bind_parameter_name(param_i) {
                     if name.starts_with('?') {
@@ -77,7 +77,7 @@ impl SqliteArguments<'_> {
                     ));
                 }
 
-                self.values[n - 1].bind(handle, param_i + 1)?;
+                self.values[n - 1].bind(handle, param_i)?;
             }
         }
 

sqlx-core/src/sqlite/statement/handle.rs

@@ -142,6 +142,7 @@ impl StatementHandle {
     }
 
     // Name Of A Host Parameter
+    // NOTE: The first host parameter has an index of 1, not 0.
     #[inline]
     pub(crate) fn bind_parameter_name(&self, index: usize) -> Option<&str> {
         unsafe {

tests/sqlite/sqlite.rs

@@ -1,7 +1,6 @@
 use futures::TryStreamExt;
-use sqlx::{
-    query, sqlite::Sqlite, Connect, Connection, Executor, Row, SqliteConnection, SqlitePool,
-};
+use sqlx::sqlite::{Sqlite, SqliteConnection, SqlitePool, SqliteRow};
+use sqlx::{query, Connect, Connection, Executor, Row};
 use sqlx_test::new;
 
 #[sqlx_macros::test]
@@ -75,6 +74,40 @@ async fn it_fetches_and_inflates_row() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[sqlx_macros::test]
+async fn it_maths() -> anyhow::Result<()> {
+    let mut conn = new::<Sqlite>().await?;
+
+    let value = sqlx::query("select 1 + ?1")
+        .bind(5_i32)
+        .try_map(|row: SqliteRow| row.try_get::<i32, _>(0))
+        .fetch_one(&mut conn)
+        .await?;
+
+    assert_eq!(6i32, value);
+
+    Ok(())
+}
+
+#[sqlx_macros::test]
+async fn it_binds_positional_parameters_issue_467() -> anyhow::Result<()> {
+    let mut conn = new::<Sqlite>().await?;
+
+    let row: (i32, i32, i32, i32) = sqlx::query_as("select ?1, ?1, ?3, ?2")
+        .bind(5_i32)
+        .bind(500_i32)
+        .bind(1020_i32)
+        .fetch_one(&mut conn)
+        .await?;
+
+    assert_eq!(row.0, 5);
+    assert_eq!(row.1, 5);
+    assert_eq!(row.2, 1020);
+    assert_eq!(row.3, 500);
+
+    Ok(())
+}
+
 #[sqlx_macros::test]
 async fn it_fetches_in_loop() -> anyhow::Result<()> {
     // this is trying to check for any data races