[mssql] Support single-quoted column aliases

tests/sqlparser_common.rs

@@ -212,6 +212,21 @@ fn parse_column_aliases() {
     one_statement_parses_to("SELECT a.col + 1 newname FROM foo AS a", &sql);
 }
 
+#[test]
+fn test_eof_after_as() {
+    let res = parse_sql_statements("SELECT foo AS");
+    assert_eq!(
+        ParserError::ParserError("Expected an identifier after AS, found: EOF".to_string()),
+        res.unwrap_err()
+    );
+
+    let res = parse_sql_statements("SELECT 1 FROM foo AS");
+    assert_eq!(
+        ParserError::ParserError("Expected an identifier after AS, found: EOF".to_string()),
+        res.unwrap_err()
+    );
+}
+
 #[test]
 fn parse_select_count_wildcard() {
     let sql = "SELECT COUNT(*) FROM customer";