Question

以下代码仅在给定ID为null时更新字段。

$sql="UPDATE TABLE7 set SCORE1= $high where SCORE1 IS NULL AND ID = 9";

如何调整代码，使其仅在null时更新行，如果不为null，则检查下一行是否为某个ID = 9等。类似的东西：

$sql="UPDATE TABLE7 set
IF SCORE1 IS NULL THEN SCORE1= $high,
ELSE   //MEANING SCORE1 IS NOT NULL
IF SCORE2 IS NULL THEN SCORE2= $high,
ELSE   //  MEANING SCORE2 IS NOT NULL
IF SCORE3 IS NULL THEN SCORE3= $high
ELSE  //MEANING ALL FIELDS ARE NOT NULL
THROW ERROR (ECHO ‘All FIELDS ARE FILLED’)
WHERE ID = 9"

谢谢。

修改

我想要的是，在更新第一个NULL字段后，其他字段将不会更新。

即如果SCORE1 = NULL，则SCORE1 = $ high但SCORE2和SCORE3不应更新，无论是否为NULL。

我只想更新第一个NULL字段。我怎样才能做到这一点？感谢。

Answer 1

UPDATE TABLE7 
set SCORE1 = case when SCORE1 IS NULL THEN $high else SCORE1 end,
    SCORE2 = case when SCORE2 IS NULL and SCORE1 is not null THEN $high else SCORE2 end,
    SCORE3 = case when SCORE3 IS NULL and SCORE1 is not null and score2 is not null THEN $high else SCORE3 end
WHERE ID = 9
and (score1 is null or score2 is null or score3 is null)

Sql-Update字段仅在空ELSE检查下一行时

1 个答案: