objective-c - 如何从数据库中获取列表，其中 name = "Elephant"in ios

Question

大家好我想从数据库中获取大象列表我正在使用这段代码但是查询是错误的 当我运行相同的查询 MesaSQLite 它正在工作时请帮助我

-(NSMutableArray*)getAnimalsList
{   
    [animalsList removeAllObjects];

    sqlite3_stmt* statement;
    const char *sql;
    sql =  "select * from animals where name = Elephant";

    if (sqlite3_prepare_v2(database, sql, -1, &statement, NULL) != SQLITE_OK) 
    {
        NSAssert1(0, @"Error: failed to prepare statement with message '%s'.", sqlite3_errmsg(database));
    }


    while (sqlite3_step(statement) == SQLITE_ROW) 
    {

        NSInteger primaryKey = sqlite3_column_int(statement,0);     
        Animal *animalObject = [[Animal alloc] initWithPrimaryKey:primaryKey database:database];
        [animalsList addObject:animalObject];
        [animalObject release];
        animalObject = nil;

    }
    sqlite3_finalize(statement);

    printf("\n The animals list count is :%d",[animalsList count]);
    return animalsList ;

}

当我在 SQLite 中使用 'SELECT * From animals where name = "Elephant";"时它正在工作

Answer 1

您没有在代码中将 Elephant 括在引号中，尝试

sql =  "select * from animals where name = 'Elephant'";