如何更新SQLite表與新列？

Question

SQLite中，我的表如下：

--------------------- 
Date   Temp 
--------------------- 
201309010051 82 
201309010151 81 
201309010251 80 
--------------------- 

我生成一個查詢，如下所示，其修改日期時間格式從201309010051到2013年9月1日00:51。

下面是我用「日期」一欄做所有值查詢：

select substr(Date, 1, 4)||"-"||substr(Date, 5, 2)||"-"||substr(Date, 7, 2) 
||" "||substr(Date, 9, 2)||":"||substr(Date, 11, 2) as CreatedColumn 
from myTable 

現在，我想將「CreatedColumn」添加到我的原始表。我試過如下：

update myTable set CreatedColumn = <my above query which modifies the datetime format> 

但是，它返回以下錯誤：

(sqlite3.OperationalError) near "select": syntax error 

我如何添加/追加從我的查詢產生的原始表「CreatedColumn」？

Answer 1

如果你已經列CreatedColumn可以設置列的值與下面的查詢每一行：

UPDATE 
    myTable 
SET 
    CreatedColumn = substr(Date, 1, 4)||"-"||substr(Date, 5, 2)||"-"||substr(Date, 7, 2) ||" "||substr(Date, 9, 2)||":"||substr(Date, 11, 2) 

Answer 2

即@Dekel寫是將數據正確的查詢。在將信息添加到新列之前，您必須首先創建它。

- 表和數據的插入的初始創建：

DROP TABLE IF EXISTS `myTable`; 
CREATE TABLE `myTable`(
    `Date` int, 
    `Temp` int 
); 

INSERT INTO `myTable` VALUES (201309010051,82), 
          (201309010151,81), 
          (201309010251,80); 

- SELECT *：

SELECT * FROM `myTable`; 
+------------+------+ 
| Date  | Temp | 
+------------+------+ 
| 2147483647 | 82 | 
| 2147483647 | 81 | 
| 2147483647 | 80 | 
+------------+------+ 
3 rows in set (0.00 sec) 

- ALTER TABLE

ALTER TABLE `myTable` ADD COLUMN `CreatedColumn` DATETIME; 

SELECT * FROM `myTable`; 
    +------------+------+---------------+ 
    | Date  | Temp | CreatedColumn | 
    +------------+------+---------------+ 
    | 2147483647 | 82 | NULL   | 
    | 2147483647 | 81 | NULL   | 
    | 2147483647 | 80 | NULL   | 
    +------------+------+---------------+ 
    3 rows in set (0.00 sec) 

- 更新CreatedColumn - 使用德克爾的命令

UPDATE 
    `myTable` 
SET 
    `CreatedColumn` = substr(Date, 1, 4)||"-"||substr(Date, 5, 2)||"-"||substr(Date, 7, 2) ||" "||substr(Date, 9, 2)||":"||substr(Date, 11, 2); 

個

- 顯示錶

SELECT * FROM `myTable`; 
    +------------+------+---------------------+ 
    | Date  | Temp | CreatedColumn  | 
    +------------+------+---------------------+ 
    | 2147483647 | 82 | 0000-00-00 00:00:00 | 
    | 2147483647 | 81 | 0000-00-00 00:00:00 | 
    | 2147483647 | 80 | 0000-00-00 00:00:00 | 
    +------------+------+---------------------+ 
    3 rows in set (0.00 sec)