Allow LIMIT/OFFSET/FETCH without FROM

Postgres allows it, as does ANSI SQL per the <query expression> definition:
https://jakewheat.github.io/sql-overview/sql-2011-foundation-grammar.html#_7_13_query_expression

Author: nickolay

src/dialect/keywords.rs

@@ -420,16 +420,16 @@ define_keywords!(
 /// can be parsed unambiguously without looking ahead.
 pub const RESERVED_FOR_TABLE_ALIAS: &[&str] = &[
     // Reserved as both a table and a column alias:
-    WITH, SELECT, WHERE, GROUP, ORDER, UNION, EXCEPT, INTERSECT,
+    WITH, SELECT, WHERE, GROUP, ORDER, LIMIT, OFFSET, FETCH, UNION, EXCEPT, INTERSECT,
     // Reserved only as a table alias in the `FROM`/`JOIN` clauses:
-    ON, JOIN, INNER, CROSS, FULL, LEFT, RIGHT, NATURAL, USING, LIMIT, OFFSET, FETCH,
+    ON, JOIN, INNER, CROSS, FULL, LEFT, RIGHT, NATURAL, USING,
 ];
 
 /// Can't be used as a column alias, so that `SELECT <expr> alias`
 /// can be parsed unambiguously without looking ahead.
 pub const RESERVED_FOR_COLUMN_ALIAS: &[&str] = &[
     // Reserved as both a table and a column alias:
-    WITH, SELECT, WHERE, GROUP, ORDER, UNION, EXCEPT, INTERSECT,
+    WITH, SELECT, WHERE, GROUP, ORDER, LIMIT, OFFSET, FETCH, UNION, EXCEPT, INTERSECT,
     // Reserved only as a column alias in the `SELECT` clause:
     FROM,
 ];

tests/sqlparser_common.rs

@@ -216,6 +216,9 @@ fn parse_limit_is_not_an_alias() {
     // In dialects supporting LIMIT it shouldn't be parsed as a table alias
     let ast = verified_query("SELECT id FROM customer LIMIT 1");
     assert_eq!(Some(ASTNode::SQLValue(Value::Long(1))), ast.limit);
+
+    let ast = verified_query("SELECT 1 LIMIT 5");
+    assert_eq!(Some(ASTNode::SQLValue(Value::Long(5))), ast.limit);
 }
 
 #[test]
@@ -2194,6 +2197,8 @@ fn parse_offset() {
         },
         _ => panic!("Test broke"),
     }
+    let ast = verified_query("SELECT 'foo' OFFSET 0 ROWS");
+    assert_eq!(ast.offset, Some(ASTNode::SQLValue(Value::Long(0))));
 }
 
 #[test]
@@ -2213,6 +2218,8 @@ fn parse_fetch() {
     };
     let ast = verified_query("SELECT foo FROM bar FETCH FIRST 2 ROWS ONLY");
     assert_eq!(ast.fetch, Some(FETCH_FIRST_TWO_ROWS_ONLY));
+    let ast = verified_query("SELECT 'foo' FETCH FIRST 2 ROWS ONLY");
+    assert_eq!(ast.fetch, Some(FETCH_FIRST_TWO_ROWS_ONLY));
     let ast = verified_query("SELECT foo FROM bar FETCH FIRST ROWS ONLY");
     assert_eq!(
         ast.fetch,