使用表中的值更新 mysql 数据库

Question

I have made some changes to an existing mysql database structure and want to update old values to new fields in a table using an id from another table. The structures are as follows:

table1

+---------+--------+
| sale_id | type   |
+---------+--------+
| 110     | credit |
| 111     | cash   |
| 112     | credit |
+---------+--------+

table2

+---------+--------+---------+-----------------+---------------+
| sale_id | item_id|   price |  payment_type   |  total_amount |
+---------+--------+---------+-----------------+---------------+
| 110     | 1      |   20    |                 |               |    
| 111     | 2      |   30    |                 |               |
| 112     | 3      |   45    |                 |               |
| 112     | 4      |   15    |                 |               |
+---------+--------+---------+-----------------+---------------+

Now I want to update the payment_type and total_amount in table2 using sale_id from table1 as reference.

Expected result after table2 is updated

+---------+--------+---------+-----------------+---------------+
| sale_id | item_id|   price |  payment_type   |  total_amount |
+---------+--------+---------+-----------------+---------------+
| 110     | 1      |   20    |      credit     |      20       |    
| 111     | 2      |   30    |      cash       |      30       |
| 112     | 3      |   45    |      credit     |      45       |
| 112     | 4      |   15    |      credit     |      15       |
+---------+--------+---------+-----------------+---------------+

My current attempt is not working and throwing an error.

Example on fidddle

CREATE TABLE table1(
   sale_id INTEGER  NOT NULL PRIMARY KEY 
  ,type  VARCHAR(6) NOT NULL
);
INSERT INTO table1(sale_id,type) VALUES (110,'Credit');
INSERT INTO table1(sale_id,type) VALUES (111,'Cash');
INSERT INTO table1(sale_id,type) VALUES (112,'Credit');


CREATE TABLE table2(
   sales_id INTEGER  NOT NULL PRIMARY KEY 
  ,item_id  VARCHAR(6) NOT NULL
  ,price  VARCHAR(6) NOT NULL
  ,payment_type  VARCHAR(6) NOT NULL
  ,total_amount  VARCHAR(6) NOT NULL
);

INSERT INTO table2(sales_id,item_id,price,payment_type,total_amount) VALUES (110,1,20,'','');
INSERT INTO table2(sales_id,item_id,price,payment_type,total_amount) VALUES (111,2,30,'','');
INSERT INTO table2(sales_id,item_id,price,payment_type,total_amount) VALUES (112,3,45,'','');
INSERT INTO table2(sales_id,item_id,price,payment_type,total_amount) VALUES (112,4,15,'','');


UPDATE table2 SET total_amount = 
    (SELECT price
        FROM table2
        INNER JOIN table1 ON sale_id = sales_id
        );
UPDATE table2 SET payment_type = 
    (SELECT type
        FROM table2
        INNER JOIN table1 ON sale_id = sales_id
        );

    
    

Answer 1

That's the update/join syntax:

update table2 t2
inner join table1 t1 on t1.sale_id = t2.sale_id
set t2.payment_type = t1.type, t2.total_amount = t2.price

Answer 2

You can update table using update clause

UPDATE table2
INNER JOIN table1
ON table2.sale_id = table1.sale_id
SET table2.payment_type = table1.type
    table2.total_amount = table2.price ;

FOR MORE PRACTICE ON UPDATE JOIN PLEASE FOLLOW BELOW LINK

UPDATE JOIN

Answer 3

I think you try to use wrong approach. Instead normalize data and use JOIN you going to de-normalize data. I advice to use different tables for sales and sale_items, but fetch data from both tables on demand like:

CREATE TABLE payment_types (
   id INTEGER  NOT NULL PRIMARY KEY 
  ,type  VARCHAR(6) NOT NULL
);
INSERT INTO payment_types VALUES (1,'Credit'), (2,'Cash');

CREATE TABLE sales (
   id INTEGER  NOT NULL PRIMARY KEY 
  ,payment_type_id  INTEGER NOT NULL
);
INSERT INTO sales(id,payment_type_id) VALUES (110,1), (111,2), (112,1);

CREATE TABLE sale_items (
   sale_id INTEGER  NOT NULL
  ,item_id  INTEGER NOT NULL
  ,price  INTEGER NOT NULL
  ,quantity  INTEGER NOT NULL
);

INSERT INTO sale_items (sale_id,item_id,price,quantity) VALUES 
(110,1,20,1), (111,2,30,2), (112,3,45,1), (112,4,15,1);

select 
    sale_id,
    pt.type,
    si.*,
    price * quantity as total_amount
from sales s
join payment_types pt on pt.id = s.payment_type_id
join sale_items si on si.sale_id = s.id;

Try SQL online here Result

+=========+========+=========+=======+==========+==============+
| sale_id | type   | item_id | price | quantity | total_amount |
+=========+========+=========+=======+==========+==============+
| 110     | Credit | 1       | 20    | 1        | 20           |
+---------+--------+---------+-------+----------+--------------+
| 111     | Cash   | 2       | 30    | 2        | 60           |
+---------+--------+---------+-------+----------+--------------+
| 112     | Credit | 3       | 45    | 1        | 45           |
+---------+--------+---------+-------+----------+--------------+
| 112     | Credit | 4       | 15    | 1        | 15           |
+---------+--------+---------+-------+----------+--------------+