在 SELECT 语句中将两个子查询合并为一个？

Question

Is there a best way to make this SELECT statement with these two subqueries ?

SELECT N.ID, N.NAME 
   (SELECT TR.PUZZLE 
    FROM puzzles TR
    WHERE TR.TEAMID = "152" 
      AND TR.NID= N.ID) AS PUZZLE_OK,
   (SELECT TR.PUZZLE_BIS 
    FROM puzzles TR
    WHERE TR.TEAMID = "152" 
      AND TR.NID= N.ID) AS PUZZLE_BIS_OK
FROM news N
WHERE N.SERIESID = "1"

Answer 1

You can rewrite your query using a JOIN instead:

SELECT N.ID, N.NAME, TR.PUZZLE AS PUZZLE_OK, TR.PUZZLE_BIS AS PUZZLE_BIS_OK
FROM news N
JOIN puzzles TR ON TR.NID = N.ID
WHERE N.SERIESID = "1"
  AND TR.TEAMID = "152"

Note that if it's possible no entry in puzzles exists for a given ID value from news , you should use a LEFT JOIN and move the WHERE condition on puzzles into the JOIN . This will then return NULL values for PUZZLE_OK and PUZZLE_BIS_OK in the same way as your subqueries will:

SELECT N.ID, N.NAME, TR.PUZZLE AS PUZZLE_OK, TR.PUZZLE_BIS AS PUZZLE_BIS_OK
FROM news N
LEFT JOIN puzzles TR ON TR.NID = N.ID AND TR.TEAMID = "152"
WHERE N.SERIESID = "1"

Note I've changed the alias on news to N to keep the SELECT clause consistent with what was in the subqueries in your question.