mySQL如何将NULL显示为0

Question

尝试让我的代码在不存在数据时显示 0 而不是 NULL:

SELECT e.EntryName AS Name, e.EntryDate AS Date,

(SELECT COALESCE(COUNT(l.crashNumber), 0)
FROM Crash l
WHERE l.crashName = e.EntryName 
AND l.crashDate = e.EntryDate
GROUP BY l.crashNumber
ORDER BY COUNT(l.crashNumber) DESC
LIMIT 1)

FROM 
(SELECT e.EntryName, e.EntryDate
FROM Entry e
GROUP BY e.EntryName, e.EntryDate)

e;

正如你所看到的，我尝试过使用 COALESCE，我也尝试过使用 ISNULL。 这个想法是，并非所有比赛都会崩溃，因此它们的输出显示为 NULL，尽管我希望当它为 NULL 时，它应该显示 0。

Answer 1

用途:

SELECT e.raceEntryRaceName AS raceName, e.raceEntryRaceDate AS raceDate,

Coalesce( ( SELECT COUNT(l.pitstopRaceNumber)
           FROM PitStops l
           WHERE l.pitstopRaceName = e.raceEntryRaceName 
             AND l.pitstopRaceDate = e.raceEntryRaceDate
           GROUP BY l.pitstopRaceNumber
           ORDER BY COUNT(l.pitstopRaceNumber) DESC
           LIMIT 1), 0) AS mostPitstops

FROM .....