Find centralized, trusted content and collaborate around the technologies you use most.
Teams
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
如何获取列中所有属性的列表。有这么多行对它们进行排序不起作用,因为我必须遍历每一行并计算每个不同的属性。我猜大约有 10 - 20 个不同的属性,但有超过 500000 行 - 任何帮助表示赞赏!
如果您想查看列中的不同值并计算该值出现的频率:
select the_column, count(*) from the_table group by the_column;
select distinct column_value from table