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;更多推荐
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