Fix incorrect LIMIT/OFFSET parsing of form LIMIT x,y

In this case x is the OFFSET and y is the LIMIT, not the
other way around.

parser/src/parser.rs

@@ -2603,16 +2603,24 @@ impl<'a> Parser<'a> {
             return Ok(None);
         }
 
-        let limit = self.parse_expr(0)?;
-        let offset = match self.peek()? {
+        let expr = self.parse_expr(0)?;
+        let (limit, offset) = match self.peek()? {
             Some(tok) => match tok.token_type.unwrap() {
-                TK_OFFSET | TK_COMMA => {
-                    eat_assert!(self, TK_OFFSET, TK_COMMA);
-                    Some(self.parse_expr(0)?)
+                TK_COMMA => {
+                    eat_assert!(self, TK_COMMA);
+                    let offset = expr;
+                    let limit = self.parse_expr(0)?;
+                    (limit, Some(offset))
                 }
-                _ => None,
+                TK_OFFSET => {
+                    eat_assert!(self, TK_OFFSET);
+                    let limit = expr;
+                    let offset = self.parse_expr(0)?;
+                    (limit, Some(offset))
+                }
+                _ => (expr, None),
             },
-            _ => None,
+            _ => (expr, None),
         };
 
         Ok(Some(Limit {

testing/offset.test

@@ -44,4 +44,17 @@ do_execsql_test select-offset-subquery {
 6|Nicholas|89
 5|Edward|15
 4|Jennifer|33
-3|Tommy|18}
+3|Tommy|18}
+
+do_execsql_test_on_specific_db {:memory:} select-limit-comma-offset-equivalence {
+    CREATE TABLE nums (x INTEGER);
+    INSERT INTO nums VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
+    SELECT x FROM nums ORDER BY x LIMIT 3 OFFSET 2;
+    SELECT x FROM nums ORDER BY x LIMIT 2,3;
+} {3
+4
+5
+3
+4
+5}
+