mysql - Mysql按条件计数记录，选择多个字段

Question

我尝试使用计数案例来计算某个列（runs.Finish）中的记录（如果它们等于一个）。

当我像下面第三行那样添加计数案例时，我似乎无法让它工作。

SELECT
  `jockeys`.`JockeyInitials`,
  `jockeys`.`JockeySurName` ,
  COUNT(  `runs`.`JockeysID` ), 
  COUNT( CASE WHEN `runs`.`Finish`=1 THEN 1 ELSE NULL END ) AS `runs`.`Finish` , 
  SUM(  `runs`.`StakeWon` ) 
FROM runs, jockeys
WHERE  `runs`.`JockeysID` =  `jockeys`.`JockeysID` 
  AND  `runs`.`JockeysID` >=1
  AND  `runs`.`JockeysID` <=100
GROUP BY  `runs`.`JockeysID`

Answer 1

您的查询应该是（按列检查分组和案例语句列的别名）

SELECT
  `jockeys`.`JockeyInitials`,
  `jockeys`.`JockeySurName` ,
  COUNT(  `runs`.`JockeysID` ), 
  COUNT( CASE WHEN `runs`.`Finish`=1 THEN 1 ELSE NULL END ) AS `Finish` , 
  SUM(  `runs`.`StakeWon` ) 
FROM runs, jockeys
WHERE  `runs`.`JockeysID` =  `jockeys`.`JockeysID` 
  AND  `runs`.`JockeysID` >=1
  AND  `runs`.`JockeysID` <=100
GROUP BY  `jockeys`.`JockeyInitials`,
  `jockeys`.`JockeySurName`