如何在SQL case语句中选择2个值？(How to select 2 values in SQL case statement?)

如何在SQL case语句中选择2个值？(How to select 2 values in SQL case statement?)

考虑这个查询：

SELECT CASE WHEN identifier = 'V' THEN pos_x, pos_y WHEN identifier = 'D' THEN height, weight END FROM sprite_data;

这会产生错误，因为（我如何理解）case语句只能返回一个值，但我试图返回2个值（pos_x和pos_y OR高度和宽度）。 如何使case语句返回两个值？

Consider this query:

SELECT CASE WHEN identifier = 'V' THEN pos_x, pos_y WHEN identifier = 'D' THEN height, weight END FROM sprite_data;

This generates an error, because (how I understand it) the case statement can only return one value, but I am trying to return 2 values (pos_x and pos_y OR height and width). How can I make the case statement return two values?

最满意答案

你不能让一个案例返回两个值。 你可以这样做：

SELECT CASE WHEN identifier = 'V' THEN pos_x WHEN identifier = 'D' THEN height END AS x, CASE WHEN identifier = 'V' THEN pos_y WHEN identifier = 'D' THEN weight END AS y FROM sprite_data;

You can't make a case return two values. You can do this:

SELECT CASE WHEN identifier = 'V' THEN pos_x WHEN identifier = 'D' THEN height END AS x, CASE WHEN identifier = 'V' THEN pos_y WHEN identifier = 'D' THEN weight END AS y FROM sprite_data;