的NSString stringWithFormat事與願違的結果

Question

我要讓SQL SELECT一句話是這樣的：

NSLog(@"sql = %@",[NSString stringWithFormat:@"select * from Table1 Where ID = %i AND '%@' = strftime('%Y',startDate)",ID,date]); 

，但它打印對我說：

sql = select * from Table1 Where ID = 1 AND '2012' = strftime('Y',startDate) 

％Y變成Y，我怎麼能避免這種情況？

Answer 1

添加另一個%逃離%字符：

NSLog(@"sql = %@",[NSString stringWithFormat:@"select * from Table1 Where ID = %i AND '%@' = strftime('%%Y',startDate)",ID,date]); 

Answer 2

添加％這樣NSLog(@"sql = %@",[NSString stringWithFormat:@"select * from Table1 Where ID = %i AND '%@' = strftime('%%Y',startDate)",ID,date]);