From 45fc758c8b0f25a18d127009b69087a6cebff175 Mon Sep 17 00:00:00 2001
From: git-hulk <hulk.website@gmail.com>
Date: Tue, 27 Aug 2024 18:50:55 +0800
Subject: [PATCH] Fix identifier starts with `$` should be regarded as a
 placeholder in SQLite

Currently, `$var` would be parsed as an identifier instead of
a placeholder in SQLite dialect, which is unexpected from the SQLite's
documentation: https://www.sqlite.org/lang_expr.html#varparam.

This relates to the issue comment: https://github.com/sqlparser-rs/sqlparser-rs/issues/291#issuecomment-2309797948
---
 src/dialect/sqlite.rs     |  1 -
 tests/sqlparser_sqlite.rs | 17 +++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/dialect/sqlite.rs b/src/dialect/sqlite.rs
index daad6a159..cc08d7961 100644
--- a/src/dialect/sqlite.rs
+++ b/src/dialect/sqlite.rs
@@ -41,7 +41,6 @@ impl Dialect for SQLiteDialect {
         ch.is_ascii_lowercase()
             || ch.is_ascii_uppercase()
             || ch == '_'
-            || ch == '$'
             || ('\u{007f}'..='\u{ffff}').contains(&ch)
     }
 
diff --git a/tests/sqlparser_sqlite.rs b/tests/sqlparser_sqlite.rs
index 629ab5fc2..ce11b015a 100644
--- a/tests/sqlparser_sqlite.rs
+++ b/tests/sqlparser_sqlite.rs
@@ -20,6 +20,7 @@ mod test_utils;
 use test_utils::*;
 
 use sqlparser::ast::SelectItem::UnnamedExpr;
+use sqlparser::ast::Value::Placeholder;
 use sqlparser::ast::*;
 use sqlparser::dialect::{GenericDialect, SQLiteDialect};
 use sqlparser::parser::{ParserError, ParserOptions};
@@ -470,6 +471,22 @@ fn parse_start_transaction_with_modifier() {
     );
 }
 
+#[test]
+fn test_dollar_identifier_as_placeholder() {
+    // This relates to the discussion in issue #291. The `$id` should be treated as a placeholder,
+    // not as an identifier in SQLite dialect.
+    //
+    // Reference: https://www.sqlite.org/lang_expr.html#varparam
+    match sqlite().verified_expr("id = $id") {
+        Expr::BinaryOp { op, left, right } => {
+            assert_eq!(op, BinaryOperator::Eq);
+            assert_eq!(left, Box::new(Expr::Identifier(Ident::new("id"))));
+            assert_eq!(right, Box::new(Expr::Value(Placeholder("$id".to_string()))));
+        }
+        _ => unreachable!(),
+    }
+}
+
 fn sqlite() -> TestedDialects {
     TestedDialects {
         dialects: vec![Box::new(SQLiteDialect {})],