fix: avoid derived table wrapping for SQL Server TOP pagination

Replace derived table wrapping with direct TOP injection for SQL Server
to prevent error 8155 when inner SELECT produces unnamed columns (e.g.
SELECT @@version). Also preserves ORDER BY that was incorrectly stripped
by the previous approach.

crates/dbx-core/src/query_result_sql.rs

@@ -156,21 +156,17 @@ pub fn build_paginated_query_sql(options: PaginatedQuerySqlOptions) -> QuerySqlB
 
     let safe_limit = options.limit.max(1);
     let safe_offset = options.offset;
-    let alias = quote_table_identifier(options.database_type, "dbx_page");
-    let wrapped_sql = if options.database_type == Some(DatabaseType::SqlServer) {
-        sql_server_statement_for_derived_table(&statement)
-    } else {
-        statement
-    };
-    let base = format!("SELECT * FROM ({wrapped_sql}) {alias}");
 
     if options.database_type == Some(DatabaseType::SqlServer) {
         if safe_offset > 0 {
             return err("unsupported");
         }
-        return ok(format!("SELECT TOP ({safe_limit}) * FROM ({wrapped_sql}) {alias}"));
+        return ok(add_sql_server_top(&statement, safe_limit));
     }
 
+    let alias = quote_table_identifier(options.database_type, "dbx_page");
+    let base = format!("SELECT * FROM ({statement}) {alias}");
+
     if options.database_type.is_some_and(uses_fetch_first) {
         let offset_sql = if safe_offset > 0 { format!(" OFFSET {safe_offset} ROWS") } else { String::new() };
         return ok(format!("{base}{offset_sql} FETCH FIRST {safe_limit} ROWS ONLY"));
@@ -324,6 +320,14 @@ fn has_top_level_select_into(sql: &str) -> bool {
     false
 }
 
+fn add_sql_server_top(sql: &str, limit: usize) -> String {
+    if sql.len() >= 6 && sql[..6].to_ascii_uppercase() == "SELECT" {
+        format!("SELECT TOP ({limit}){}", &sql[6..])
+    } else {
+        format!("SELECT TOP ({limit}) * FROM ({sql}) [dbx_page]")
+    }
+}
+
 fn sql_server_statement_for_derived_table(statement: &str) -> String {
     let Some(order_by) = find_top_level_trailing_order_by(statement) else {
         return statement.to_string();
@@ -568,7 +572,20 @@ mod tests {
         });
 
         assert_eq!(result.ok, true);
-        assert_eq!(result.sql.unwrap(), "SELECT TOP (100) * FROM (SELECT id FROM users) [dbx_page]");
+        assert_eq!(result.sql.unwrap(), "SELECT TOP (100) id FROM users ORDER BY id DESC");
+    }
+
+    #[test]
+    fn wraps_sqlserver_select_with_unnamed_column() {
+        let result = build_paginated_query_sql(PaginatedQuerySqlOptions {
+            original_sql: "SELECT @@version".to_string(),
+            database_type: Some(DatabaseType::SqlServer),
+            limit: 100,
+            offset: 0,
+        });
+
+        assert_eq!(result.ok, true);
+        assert_eq!(result.sql.unwrap(), "SELECT TOP (100) @@version");
     }
 
     #[test]