iphone - 如何使用iPhone中的where子句从sqlite表中获取数据

Question

我在正常情况下从两个表中选择数据，它工作正常，但如果我使用 where 子句，它不会返回任何内容。

这里是查询

NSString *select =[NSString stringWithFormat:@"SELECT *from ContentMaster As ml LEFT JOIN ContentTagging As cat ON cat.ContentID = ml.ContentID where cat.ContenTagText= %@" , appDelegate.tagInput];

这里是查询的NSLog

SELECT *from ContentMaster As ml LEFT JOIN ContentTagging  ON cat.ContentID = ml.ContentID where cat.ContenTagText= Tag1

Answer 1

在比较字符串时将您的 ContenTagText 放入 ''

NSString *select =[NSString stringWithFormat:@"SELECT * from ContentMaster As ml LEFT JOIN ContentTagging As cat ON cat.ContentID = ml.ContentID where cat.ContenTagText= \'%@\'" , appDelegate.tagInput];

查询将是:

SELECT *from ContentMaster As ml LEFT JOIN ContentTagging  ON cat.ContentID = ml.ContentID where cat.ContenTagText= 'Tag1'

希望能有所帮助。