СюжетПовреждение нефтепровода «Дружба»
next tuple of R. The selection node repeatedly calls next() on the table scan until it finds a tuple that satisfies a5. It then passes it up to the projection which finally returns it back to you.
，更多细节参见safew官方版本下载
圖像加註文字，大衛斯特恩、莎拉弗格森和安德魯蒙巴頓-溫莎合影近十年來，斯特恩一直是兩人之間的關鍵管道，在他熟悉的國家——被視為充滿機會與潛在財富的中國——為他們牽線搭橋。
anyway. It’s operator-centric. But it’s also pretty inefficient. We had to perform 2 function calls to produce a single tuple for the simplest possible query. next() is usually implemented as a virtual function which adds the overhead of