mysql - MySQL如何构建Where子句

Answer 1

where (Table.table_who<>"aaa") OR (Format(Now()-[table_when],"hh")<12 AND Table.table_who="aaa") 

如果我理解正确的话。哪里不是 aaa 或者现在是 aaa - 当 > 12 时？

Answer 2

请尝试：

   SELECT Table.table_id, Table.table_who, Table.table_whom, Table.table_when, Format(Now()-  [table_when],"hh") AS Diff
    FROM [Table]
    WHERE (((Table.table_who)<>"aaa") AND ((Format(Now()-[table_when],"hh"))<12))
    OR (((Table.table_who)="aaa") AND ((Format(Now()-[table_when],"hh"))<12))

Answer 3

试试这个代码：

SELECT Table.table_id, Table.table_who, Table.table_whom, Table.table_when, Format(Now()-[table_when],"hh") AS Diff
    FROM [Table]
    WHERE (Table.table_who)<>"aaa") 
    OR ((Table.table_who)="aaa") AND ((Format(Now()-[table_when],"hh"))<12) ); 

Answer 4

只需像您定义的那样编写条件：

WHERE
 (Table.table_who = 'aaa' AND Format(Now() - [table_when], 'hh') < 12) OR
 Table.table_who <> 'aaa'

你只需要括号在某些情况下当然不应该过度使用它们，但我喜欢在这样的情况下将条件组合在一起，当你想要（A AND B）OR C时。如果你这样写，就不会出错关于计算表达式的顺序。

根据您的习惯，不同的缩进可能会使其更加清晰。

WHERE
 (
    Table.table_who = 'aaa' 
    AND Format(Now() - [table_when], 'hh') < 12
 ) 
 OR Table.table_who <> 'aaa'

Answer 5

我想这就是你想要的：

WHERE (Table.table_who = "aaa" AND Table.table_when > SUBDATE(CURDATE(), INTERVAL 12 DAY)) OR Table.table_who <> "aaa"