fix: handle bigquery offset in map key (#797)

* fix: handle bigquery offset in map key

* chore: add in more comments and tests

* chore: fix all linting and compilation warnings

src/parser.rs

@@ -4183,7 +4183,13 @@ impl<'a> Parser<'a> {
     pub fn parse_map_key(&mut self) -> Result<Expr, ParserError> {
         let next_token = self.next_token();
         match next_token.token {
-            Token::Word(Word { value, keyword, .. }) if keyword == Keyword::NoKeyword => {
+            // handle bigquery offset subscript operator which overlaps with OFFSET operator
+            Token::Word(Word { value, keyword, .. })
+                if (dialect_of!(self is BigQueryDialect) && keyword == Keyword::OFFSET) =>
+            {
+                self.parse_function(ObjectName(vec![Ident::new(value)]))
+            }
+            Token::Word(Word { value, keyword, .. }) if (keyword == Keyword::NoKeyword) => {
                 if self.peek_token() == Token::LParen {
                     return self.parse_function(ObjectName(vec![Ident::new(value)]));
                 }

tests/sqlparser_bigquery.rs

@@ -13,10 +13,9 @@
 #[macro_use]
 mod test_utils;
 
-use test_utils::*;
-
 use sqlparser::ast::*;
 use sqlparser::dialect::{BigQueryDialect, GenericDialect};
+use test_utils::*;
 
 #[test]
 fn parse_literal_string() {
@@ -306,3 +305,37 @@ fn bigquery_and_generic() -> TestedDialects {
         dialects: vec![Box::new(BigQueryDialect {}), Box::new(GenericDialect {})],
     }
 }
+
+#[test]
+fn parse_map_access_offset() {
+    let sql = "SELECT d[offset(0)]";
+    let _select = bigquery().verified_only_select(sql);
+    #[cfg(not(feature = "bigdecimal"))]
+    assert_eq!(
+        _select.projection[0],
+        SelectItem::UnnamedExpr(Expr::MapAccess {
+            column: Box::new(Expr::Identifier(Ident {
+                value: "d".to_string(),
+                quote_style: None,
+            })),
+            keys: vec![Expr::Function(Function {
+                name: ObjectName(vec!["offset".into()]),
+                args: vec![FunctionArg::Unnamed(FunctionArgExpr::Expr(Expr::Value(
+                    Value::Number("0".into(), false)
+                ))),],
+                over: None,
+                distinct: false,
+                special: false,
+            })],
+        })
+    );
+
+    // test other operators
+    for sql in [
+        "SELECT d[SAFE_OFFSET(0)]",
+        "SELECT d[ORDINAL(0)]",
+        "SELECT d[SAFE_ORDINAL(0)]",
+    ] {
+        bigquery().verified_only_select(sql);
+    }
+}