已解决

Question

我想使用if语句更新表A中的价格，我已经尝试过了，但是不能只通过逐个调用id来进行计算，如何直接计算价格？这是表格：

表A

-------------------------
id | type | total | price
-------------------------
1  |  a1  |   80  | [  ]
2  |  a2  |   50  | [  ] 
3  |  a2  |   15  | [  ]

这是if语句

        if($type=='a1')
        {
            $price1=1050;
            $price2=1500;
            $price3=2000;
            if($total <= 10)
            {
                $price = $total*$price1;
            }
            elseif($total <= 20)
            {
                $a = 10;
                $remtotal = $total-$a;
                $price = ($a*$price1)+($remtotal*$price2);
            }
            elseif($total > 20)
            {
                $a = 10;
                $b = 10;
                $remtotal = ($total-$a)-$b;
                $price = ($a*$price1)+($b*$price2)+($remtotal*$price3);
            }

        }
        elseif($type=='a2')
        {
            $price1=2100;
            $price2=3000;
            $price3=4000;
            if($total <= 10)
            {
                $price = $total*$price1;
            }
            elseif($total <= 20)
            {
                $a = 10;
                $remtotal = $total-$a;
                $price = ($a*$price1)+($remtotal*$price2);
            }
            elseif($total > 20)
            {
                $a = 10;
                $b = 10;
                $remtotal = ($total-$a)-$b;
                $price = ($a*$price1)+($b*$price2)+($remtotal*$price3);
            }
        }



SELECT id,type,total,price FROM TABLE A WHERE id='id'


UPDATE TABLE A SET price='$price' WHERE id=id"

我可以通过调用id来逐一计数，但是我希望可以立即将其全部计数

预期结果

-------------------------
id | type | total | price
-------------------------
1  |  a1  |   80  | [145500]
2  |  a2  |   50  | [171000] 
3  |  a2  |   15  | [28500]

如何做到？

已解决

我创建2个表

        TABLE A
-------------------------
id | type | total | price
-------------------------
1  |  a1  |   80  | [ ? ]
2  |  a2  |   50  | [ ? ] 
3  |  a2  |   15  | [ ? ]


              TABLE B
| type | price1 | price2 | price3 |
| ---- | ------ | ------ | ------ |
| a1   | 1050   | 1500   | 2000   |
| a2   | 2100   | 3000   | 4000   |
| a2   | 2100   | 3000   | 4000   |

这是代码

UPDATE tabelA ta, tabelB tb
SET ta.price = ( CASE 
       WHEN ta.type = 'a1' AND ta.total <= 10
       THEN ta.total * tb.price1

       WHEN ta.type = 'a1' AND ta.total <= 20
       THEN (10 * tb.price1) + ((ta.total - 10) * tb.price2)

       WHEN ta.type = 'a1' AND ta.total > 20
       THEN (10 * tb.price1) + (10 * tb.price2) + (((ta.total - 10) - 10) * tb.price3)

       WHEN ta.type = 'a2' AND ta.total <= 10
       THEN ta.total * tb.price1

       WHEN ta.type = 'a2' AND ta.total <= 20
       THEN (10 * tb.price1) + ((ta.total - 10) * tb.price2)

       WHEN ta.type = 'a2' AND ta.total > 20
       THEN (10 * tb.price1) + (10 * tb.price2) + (((ta.total - 10) - 10) * tb.price3)
     END )
WHERE ta.type = tb.type


        TABLE A
-------------------------
id | type | total | price
-------------------------
1  |  a1  |   80  | [145500]
2  |  a2  |   50  | [171000] 
3  |  a2  |   15  | [28500]

Answer 1

最简单的方法是制作价格表。

创建表/插入

CREATE TABLE prices (
  `id` INTEGER,
  `type` VARCHAR(2),
  `price1` DOUBLE,
  `price2` DOUBLE,
  `price3` DOUBLE
);  

INSERT INTo prices (id, type, price1, price2, price3) VALUES(1, 'a1', 1050, 1500, 2000);

然后INNER JOIN与您的真实表一起在CASE END子句中进行计算。

查询

SELECT 
 *
 , (
     CASE
       WHEN Table1.type = 'a1' AND Table1.total <= 10
       THEN Table1.total * prices.price1

       WHEN Table1.type = 'a1' AND Table1.total <= 20
       THEN (10 * prices.price1) + ((Table1.total - 10) * prices.price2)

       WHEN Table1.type = 'a1' AND Table1.total > 20
       THEN (10 * prices.price1) + (10 * prices.price2) + (((Table1.total - 10) - 10) * prices.price3)       
     END
   ) AS price_total
FROM 
 Table1
INNER JOIN 
 prices 
ON
 Table1.type = prices.type

结果

| id  | type | total | id  | type | price1 | price2 | price3 | price_total |
| --- | ---- | ----- | --- | ---- | ------ | ------ | ------ | ----------- |
| 1   | a1   | 80    | 1   | a1   | 1050   | 1500   | 2000   | 145500      |

demo

抱歉，我已经添加了预期的输出

已编辑

我刚刚注意到类型a1和a2的PHP计算代码是相同的，所以您在这里重复一遍。

查询应该/可以没有类型。

查询

SELECT 
 *
 , (
     CASE
       WHEN Table1.total <= 10
       THEN Table1.total * prices.price1

       WHEN Table1.total <= 20
       THEN (10 * prices.price1) + ((Table1.total - 10) * prices.price2)

       WHEN Table1.total > 20
       THEN (10 * prices.price1) + (10 * prices.price2) + (((Table1.total - 10) - 10) * prices.price3)       
     END
   ) AS price_total
FROM 
 Table1
INNER JOIN 
 prices 
ON
 Table1.type = prices.type

结果

| id  | type | total | id  | type | price1 | price2 | price3 | price_total |
| --- | ---- | ----- | --- | ---- | ------ | ------ | ------ | ----------- |
| 1   | a1   | 80    | 1   | a1   | 1050   | 1500   | 2000   | 145500      |
| 2   | a2   | 50    | 1   | a2   | 2100   | 3000   | 4000   | 171000      |
| 3   | a2   | 15    | 1   | a2   | 2100   | 3000   | 4000   | 36000       |

demo

否则，您需要像这样在查询中重复它。

查询

SELECT 
 *
 , (
     CASE
       WHEN Table1.type = 'a1' AND Table1.total <= 10
       THEN Table1.total * prices.price1

       WHEN Table1.type = 'a1' AND Table1.total <= 20
       THEN (10 * prices.price1) + ((Table1.total - 10) * prices.price2)

       WHEN Table1.type = 'a1' AND Table1.total > 20
       THEN (10 * prices.price1) + (10 * prices.price2) + (((Table1.total - 10) - 10) * prices.price3)       


       WHEN Table1.type = 'a2' AND Table1.total <= 10
       THEN Table1.total * prices.price1

       WHEN Table1.type = 'a2' AND Table1.total <= 20
       THEN (10 * prices.price1) + ((Table1.total - 10) * prices.price2)

       WHEN Table1.type = 'a2' AND Table1.total > 20
       THEN (10 * prices.price1) + (10 * prices.price2) + (((Table1.total - 10) - 10) * prices.price3)     
     END
   ) AS price_total
FROM 
 Table1
INNER JOIN 
 prices 
ON
 Table1.type = prices.type

使用if语句更新表

已解决

1 个答案: