Support OFFSET LIMIT as well as LIMIT OFFSET (#413)

* Inital support in current_timestamp

* Support time functions

* Add Test

* Fix order of offset

* Merge from main

* Fix PR

* Update Test

* Do not allow repeated LIMIT or OFFSET

Co-authored-by: Yuval Shkolar <yuval@illumex.ai>

src/parser.rs

@@ -2499,17 +2499,18 @@ impl<'a> Parser<'a> {
                 vec![]
             };
 
-            let limit = if self.parse_keyword(Keyword::LIMIT) {
+            let mut limit = None;
-                self.parse_limit()?
+            let mut offset = None;
-            } else {
-                None
-            };
 
-            let offset = if self.parse_keyword(Keyword::OFFSET) {
+            for _x in 0..2 {
-                Some(self.parse_offset()?)
+                if limit.is_none() && self.parse_keyword(Keyword::LIMIT) {
-            } else {
+                    limit = self.parse_limit()?
-                None
+                }
-            };
+
+                if offset.is_none() && self.parse_keyword(Keyword::OFFSET) {
+                    offset = Some(self.parse_offset()?)
+                }
+            }
 
             let fetch = if self.parse_keyword(Keyword::FETCH) {
                 Some(self.parse_fetch()?)

tests/sqlparser_common.rs

@@ -4076,6 +4076,40 @@ fn verified_expr(query: &str) -> Expr {
     all_dialects().verified_expr(query)
 }
 
+#[test]
+fn parse_offset_and_limit() {
+    let sql = "SELECT foo FROM bar LIMIT 2 OFFSET 2";
+    let expect = Some(Offset {
+        value: Expr::Value(number("2")),
+        rows: OffsetRows::None,
+    });
+    let ast = verified_query(sql);
+    assert_eq!(ast.offset, expect);
+    assert_eq!(ast.limit, Some(Expr::Value(number("2"))));
+
+    // different order is OK
+    one_statement_parses_to("SELECT foo FROM bar OFFSET 2 LIMIT 2", sql);
+
+    // Can't repeat OFFSET / LIMIT
+    let res = parse_sql_statements("SELECT foo FROM bar OFFSET 2 OFFSET 2");
+    assert_eq!(
+        ParserError::ParserError("Expected end of statement, found: OFFSET".to_string()),
+        res.unwrap_err()
+    );
+
+    let res = parse_sql_statements("SELECT foo FROM bar LIMIT 2 LIMIT 2");
+    assert_eq!(
+        ParserError::ParserError("Expected end of statement, found: LIMIT".to_string()),
+        res.unwrap_err()
+    );
+
+    let res = parse_sql_statements("SELECT foo FROM bar OFFSET 2 LIMIT 2 OFFSET 2");
+    assert_eq!(
+        ParserError::ParserError("Expected end of statement, found: OFFSET".to_string()),
+        res.unwrap_err()
+    );
+}
+
 #[test]
 fn parse_time_functions() {
     let sql = "SELECT CURRENT_TIMESTAMP()";