Question

我的数据结构如下所示

CREATE TABLE IF NOT EXISTS `admin_tax_names` (
  `sl_no` int(11) NOT NULL auto_increment,
  `tax_id` varchar(3) default NULL,
  `tax_name` varchar(50) default NULL,
  `modified_at` timestamp NOT NULL default CURRENT_TIMESTAMP,
  PRIMARY KEY  (`sl_no`)
) ;


INSERT INTO `admin_tax_names` (`sl_no`, `tax_id`, `tax_name`, `modified_at`) VALUES
    (1, 'T1', 'cost', '2015-01-22 16:55:19'),
    (2, 'T6', 'Service Tax', '2015-01-22 16:55:19'),
    (3, 'T3', 'VAT', '2015-01-22 16:55:19'),
    (4, 'T4', 'OtherTax2', '2015-01-22 16:55:19'),
    (5, 'T5', 'OtherTax1', '2015-01-22 16:55:20'),
    (6, 'T2', 'Discount', '2015-01-23 19:23:30'),
    (7, 'T7', 'Service Charge', '2015-02-09 20:48:19');

我需要在一个语句中用不同的值更新T1，T2，T3，T4，T5，T6，T7 我试过了

UPDATE admin_tax_names SET T1 = 'cost' , T2 = 'as' , T3 = 'sas' , T4 = 'sas' , T5='sas' , T6 = 'asa' , T7 ='asas';

但我得到的错误是

'字段列表

中的未知列'T1'

这是我的sqlfiddle

http://sqlfiddle.com/#!9/4c24d

你能否告诉我如何在这种情况下更新表？

Answer 1

我想你想要这样的东西：

update admin_tax_names
    set tax_name = (case tax_id
                      when 'T1' then 'cost' 
                      when 'T2' then 'as' 
                      when 'T3' then 'sas'
                      when 'T4' then 'sas'
                      when 'T5' then 'sas'
                      when 'T6' then 'asa'
                      when 'T7' then 'asas'
                  end)
    where tax_id in ('T1', 'T2', 'T3', 'T4', 'T5', 'T6', 'T7');

您似乎混淆了列名和列值之间的区别。

Answer 2

您在更新语句中使用column value代替列名

UPDATE Syntax

UPDATE [LOW_PRIORITY] [IGNORE] table_reference
    SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
    [WHERE where_condition]
    [ORDER BY ...]
    [LIMIT row_count]

这是查询;

UPDATE admin_tax_names 
SET `tax_name` = 
    case 
        when `tax_id` = 'T1' then 'cost' 
        when `tax_id` = 'T2' then 'as' 
        when `tax_id` = 'T3' then 'sas' 
        when `tax_id` = 'T4' then 'sas' 
        when `tax_id` = 'T5' then 'sas'
        when `tax_id` = 'T6' then 'asa'
        when `tax_id` = 'T7' then'asas'
        else `tax_name`
    end;

sql fiddle demo

在这种情况下如何更新多个列

2 个答案: