objective-c - 在iOS中使用SQLite混合逻辑运算符OR和AND

Question

我在SQLite数据库中有以下数据：

+----+------------+------------+
| id | start_date |  end_date  |
+----+------------+------------+
|  1 | 2014-04-22 | 2014-04-22 |
|  2 | 2014-04-22 | null       |
+----+------------+------------+

我正在尝试像这样的sql中获取两行

NSString *query = @"SELECT * FROM periods WHERE `start_date` <= ? AND (`end_date` >= ? OR `end_date` IS NULL)";
FMResultSet *set = [db executeQuery:query, date, date];

但是它仅返回第一行。

确切的sql会在Firefox的SQLite Manager加载项中正确返回它们两者。

Answer 1

要获取所有行，您只需遍历整个结果集：

NSString    *query = @"SELECT * FROM periods WHERE start_date <= ? AND (end_date >= ? OR end_date IS NULL)";
NSString    *date  = @"2014-04-22";
FMResultSet *rs    = [db executeQuery:query, date, date];

while ([rs next]) {
    NSLog(@"%@", [rs resultDictionary]);
}
[rs close];

这对我来说很好。问题不在于您的SQL，而在于代码的其他地方。