Question

我想通过查询获取我的组的数据并将它们加载到文本字段中。这是我的桌子整数ID 姓名文字持续时间真实时间真实名称列中的名称很少我尝试为每个名称调用方法，但它导致插入失败。

我想收到此查询并在特定标签上加载结果：我不知道如何获得响应

SELECT  Name,SUM (time) FROM  cost GROUP BY Name;

有我当前的代码

 NSString *docsDir;
NSArray *dirPaths;

 double totaltime = 1.0;

// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = dirPaths[0];

// Build the path to the database file
databasePath = [[NSString alloc]
                initWithString: [docsDir stringByAppendingPathComponent:
                                 @"Database.db"]];


NSString *queryString=@"SELECT SUM(DURATION) AS TOTAL FROM RECORDS";
sqlite3_stmt    *statement;

if(sqlite3_open([databasePath UTF8String], &myDatabase) == SQLITE_OK) {

    if(sqlite3_prepare_v2(myDatabase, [queryString UTF8String], -1, &statement, nil) == SQLITE_OK){
        while (sqlite3_step(statement) == SQLITE_ROW) {
             totaltime =  sqlite3_column_double(statement, 0);
            NSLog(@"The sum is  %f ", totaltime);
        }
    }
}
integer_t intotal=totaltime;
NSString* total=[NSString stringWithFormat:@"%d min",intotal];
totaltimefield.text=total;

Answer 1

这完全涵盖了nicely in the documentation，但简而言之，一旦您将SQL更新为两列：

const unsigned char* name = sqlite3_column_text(statement, 0);
double totaltime =  sqlite3_column_double(statement, 1);
NSLog(@"The sum for %s is  %f ", name, totaltime);

sqlite3_column_x函数中的第二个参数是列号。

如何在iOS中通过sqlite查询接收组的数据？

1 个答案: