如何从iphone中的sqlite表中获取连接数据

Question

我使用join来获取sqlite表中的数据，这是我的查询

select = [[NSString alloc] initWithFormat:@"select * FROM ContentMaster LEFT JOIN  Category  ON  ContentMaster.CategoryID= Category.CategoryID  LEFT JOIN Topic ON ContentMaster.TopicID=Topic.TopicID where ContentMaster.ContentTagText='%@' OR Category.CategoryName='%@' AND Topic.TopicName='%@'",appDelegate.tagInput,appDelegate.categoryName,appDelegate.topicName];

它工作正常，但我想使用此查询获取Category.CategoryName和Topic.TopicName以便如何获取以及何时获取该行，如下所示如何给出数字

if(sqlite3_prepare_v2(database, sql, -1, &selectstmt, NULL) == SQLITE_OK)
{
        while(sqlite3_step(selectstmt) == SQLITE_ROW)
        {
            NSInteger primaryKey = sqlite3_column_int(selectstmt, 0);
            Content *coffeeObj = [[Content alloc] initWithPrimaryKey:primaryKey];
            coffeeObj.categoryID  = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,1)];
            coffeeObj.topicID = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,2)];
            coffeeObj.contentType = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,3)];
            coffeeObj.contentTitle = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,4)];
            coffeeObj.contentAddedByUserID = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,5)];
            coffeeObj.contentDescription = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,6)];
            coffeeObj.contentFileName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,7)];
            coffeeObj.contentSavedFileLocation = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,8)];
            coffeeObj.contentSize = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,9)];
            coffeeObj.contentAddedDateTime = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,10)];
            coffeeObj.hiveletCode = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,11)];
            coffeeObj.contentTagText = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,12)];
            coffeeObj.views = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,13)];

            coffeeObj.userName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt,14)];
            }}

如果我得到CategoryName我必须写15或其他任何内容以及如何进入查询。