mysql - 如何在 SQL 中的另一个 select 中编写 select 语句

Question

谁能告诉我这个查询有什么问题？ 它在第二个选择附近给出语法错误

SELECT b.mc_boxes_idmc_boxes,
          t.idtitles, 
          t.title,
          t.languages_idlanguages,
          MAX(h.idtitle_history),
          MAX(h.edition)
          (SELECT h.preview, h.file WHERE h.idtitle_history = MAX(h.idtitle_history))
                        FROM mc_boxes_has_titles b
                        LEFT JOIN titles t ON b.titles_idtitles = t.idtitles
                        LEFT JOIN title_history h ON h.titles_idtitles = t.idtitles
                        WHERE b.mc_boxes_idmc_boxes = 12
                        AND h.edition IS NOT NULL
                        GROUP BY b.mc_boxes_idmc_boxes, idtitles
                        ORDER BY b.sortorder;

Answer 1

看起来你在 MAX(h.edition) 之后少了一个逗号

SELECT b.mc_boxes_idmc_boxes,
          t.idtitles, 
          t.title,
          t.languages_idlanguages,
          MAX(h.idtitle_history),
          MAX(h.edition), 
          (SELECT h.preview, h.file WHERE h.idtitle_history = MAX(h.idtitle_history))
FROM mc_boxes_has_titles b
LEFT JOIN titles t ON b.titles_idtitles = t.idtitles
LEFT JOIN title_history h ON h.titles_idtitles = t.idtitles
WHERE b.mc_boxes_idmc_boxes = 12
     AND h.edition IS NOT NULL
GROUP BY b.mc_boxes_idmc_boxes, idtitles
ORDER BY b.sortorder;

除了逗号之外，您还在子查询中选择了两个字段

SELECT b.mc_boxes_idmc_boxes,
          t.idtitles, 
          t.title,
          t.languages_idlanguages,
          MAX(h.idtitle_history),
          MAX(h.edition), 
          (SELECT preview FROM title_history WHERE idtitle_history = MAX(h.idtitle_history)),
          (SELECT [file] FROM title_history WHERE idtitle_history = MAX(h.idtitle_history))
FROM mc_boxes_has_titles b
LEFT JOIN titles t ON b.titles_idtitles = t.idtitles
LEFT JOIN title_history h ON h.titles_idtitles = t.idtitles
WHERE b.mc_boxes_idmc_boxes = 12
     AND h.edition IS NOT NULL
GROUP BY b.mc_boxes_idmc_boxes, idtitles
ORDER BY b.sortorder;