Flink SQL:Queries(ORDER BY clause)

ORDER BY clause

Batch Streaming

The ORDER BY clause causes the result rows to be sorted according to the specified expression(s). If two rows are equal according to the leftmost expression, they are compared according to the next expression and so on. If they are equal according to all specified expressions, they are returned in an implementation-dependent order.
ORDER BY子句根据指定的表达式对结果行进行排序。如果根据最左边的表达式，两行相等，则根据下一个表达式进行比较，依此类推。如果根据所有指定的表达式，它们相等，则以依赖于实现的顺序返回。

When running in streaming mode, the primary sort order of a table must be ascending on a time attribute. All subsequent orders can be freely chosen. But there is no this limitation in batch mode.
在流模式下运行时，表的主要排序顺序必须在时间属性上升序。所有后续顺序均可自由选择。但在批处理模式中没有此限制。

SELECT *
FROM Orders
ORDER BY order_time, order_id