AWS SimpleDB 选择表达式 iPhone

发布于 2024-12-05 14:36:40 字数 945 浏览 2 评论 0原文

我需要为 SimpleDB 构造一个 selectExpression，其中我只想要属性 = 到 X 的项目，按属性 Y 降序排序。到目前为止我所拥有的就是：

NSString *selectExpression = [NSString stringWithFormat:@"select itemName() from `%@`",domainString];

@try {
    SimpleDBSelectRequest  *selectRequest2  = [[[SimpleDBSelectRequest alloc] initWithSelectExpression:selectExpression] autorelease];
    SimpleDBSelectResponse *selectResponse = [[Constants sdb] select:selectRequest2];

    if (items == nil) {
        items = [[NSMutableArray alloc] initWithCapacity:[selectResponse.items count]];
    }
    else {
        [items removeAllObjects];
    }
    for (SimpleDBItem *item in selectResponse.items) {
        [items addObject:item.name];
    }
    [items sortUsingSelector:@selector(compare:)];
}
@catch (AmazonServiceException *exception) {
    NSLog(@"Exception = %@", exception);
}

我宁愿只选择属性 X by Y 的项目（上面）而不是获取所有项目然后排序。我该如何添加这个？它是放在 selectExpression 字符串中还是其他地方。非常感谢！

原文

I need to construct a selectExpression for SimpleDB where I only want items with attributes = to X, sorted in descending order by attribute Y. All I have so far is this:

NSString *selectExpression = [NSString stringWithFormat:@"select itemName() from `%@`",domainString];

@try {
    SimpleDBSelectRequest  *selectRequest2  = [[[SimpleDBSelectRequest alloc] initWithSelectExpression:selectExpression] autorelease];
    SimpleDBSelectResponse *selectResponse = [[Constants sdb] select:selectRequest2];

    if (items == nil) {
        items = [[NSMutableArray alloc] initWithCapacity:[selectResponse.items count]];
    }
    else {
        [items removeAllObjects];
    }
    for (SimpleDBItem *item in selectResponse.items) {
        [items addObject:item.name];
    }
    [items sortUsingSelector:@selector(compare:)];
}
@catch (AmazonServiceException *exception) {
    NSLog(@"Exception = %@", exception);
}

I would prefer to only select items (above) with attributes X by Y rather than get all items and then sort. How do I add this? Does it go in the selectExpression string or somewhere else. Many thanks!

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你丑哭了我 2024-12-12 14:36:40

试试这个——

Select x,y from <domain_name> where itemName() is not null order by itemName() asc

Try this out --

Select x,y from <domain_name> where itemName() is not null order by itemName() asc

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调妓 2024-12-12 14:36:40

NSString *selectExpression = [NSString stringWithFormat:@"select itemName() from `%@` where X = '%@' order by 'X' descending",domainName,attributeValue];

NSString *selectExpression = [NSString stringWithFormat:@"select itemName() from `%@` where X = '%@' order by 'X' descending",domainName,attributeValue];

回复收藏 0 原文

~没有更多了~