列计数返回零

Question

我想创建从sqlite数据库读取循环，但列数总是返回零。列= 0

sqlite3_stmt *statement; 

NSString *querySQL = @"SELECT * FROM Animations"; 

const char *query_stmt = [querySQL UTF8String]; 

if (sqlite3_prepare_v2(localDB,query_stmt, -1, &statement, NULL) == SQLITE_OK) 
{ 
    int columns = sqlite3_data_count(statement); 
    NSLog(@"Columns: %d",columns); 

    while(sqlite3_step(statement) == SQLITE_ROW) 
    { 
     for (int i=1;i<columns;i++) 
     { 
     NSString *st0 = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, i)]; 
     NSLog(@"%@",st0); 
     } 
    } 
} 

else 
{ 
    NSLog(@"%s","Error on SQLITE_OK"); 
} 

Answer 1

https://www.sqlite.org/c3ref/data_count.html

The sqlite3_data_count(P) routine returns 0 if the previous call to sqlite3_step(P) returned SQLITE_DONE. 

尝试把数据算你sqlit3_step语句后