MySQL takes the query result as the data updated by update, and concatenates it after the original field data (Lej)

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update user INNER JOIN 
(SELECT GROUP_CONCAT('',id)AS app_id_str  FROM `app` WHERE `admin_id` = ' user B Of id' AND `status` > '0' AND `is_deleted` = '0' LIMIT 0,1000 ) app_id_strs 
set app_id= CONCAT(app_id,',',app_id_str) WHERE uid= user A Of id;

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paraphrase ：

1. Inquire about app The status in the table is greater than 0, Not delete , And admin_id= user Bid All primary keys of users id, And use (,) comma Concatenate into string aliases app_id_strs ;

(SELECT GROUP_CONCAT('',id)AS app_id_str  FROM `app` WHERE `admin_id` = ' user B Of id' AND `status` > '0' AND `is_deleted` = '0' LIMIT 0,1000 ) app_id_strs 

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2. to update user A Of app_id, stay A Users' original app_id after , use CONCAT, Found on the splicing app_id_strs, And use （,） Comma connection

Expand ：

Two 、mysql in update and select Use a combination of

In need update Set parameters from other tables select The result is , Need to put update and select Use a combination of , Different data The library supports different forms , stay mysql Below :

update A inner join(select id,name from B) c on A.id = c.id set A.name = c.name;

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according to AB Two watches id Same as condition , hold A Tabular name It is amended as follows B Of sql The statement is as shown above

3、 ... and 、update and select Use it together to update data , Case study

There are two tables inspect_danger and company surface , according to company Tabular ID and inspect_danger Tabular COMPANY_ID matching , hold company In table INDUSTRY Update to inspect_danger In the table .

UPDATE inspect_danger ins
LEFT JOIN (
    SELECT 
    com.ID,com.INDUSTRY,ip.ID insId
    FROM company com
    INNER JOIN  inspect_danger ip
    ON ip.COMPANY_ID = com.ID
    GROUP BY com.ID
) c 
ON ins.ID = c.insId
SET ins.COMPANY_INDUSTRY = c.INDUSTRY

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Four 、 do SQL You often need to , Splice the results of the query into a string .

resolvent ： adopt group_concat function

1. Normal query as follows :

select id result from ctp_enum_item limit 100;

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2. Joining together the results as follows

  select group_concat("'",id,"'") result from ctp_enum_item limit 100; 

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3. Because the result of splicing is very long , The result of splicing is incomplete , It can be solved in the following ways . Execute before each query , Make the query result value larger .

SET SESSION group_concat_max_len = 10240;
 perhaps 
SET GLOBAL group_concat_max_len = 10240; 

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4. Add ：SQL server Of Splicing SQL as follows ：

select stuff((
select ','+ requestid
from nccombinedpayment for xml path('')),1,1,'') as requestid ;

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5、 ... and 、mysql Splice strings for the queried fields concat

SELECT item_starttime,item_username,CONCAT(' Go out ',item_wcaddress) as item_wcaddress,author from tlk_KQ_goout_app;

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Before splicing

After splicing

6、 ... and 、 elementary analysis MySQL in concat as well as group_concat Use

7、 ... and 、mysql Append a string to the string of a field in the table

update Table name set Field name =CONCAT( Field name ,” Values to be added ”)WHERE Conditions ;

for example ：

update np_order set customer_remark=CONCAT(customer_remark," Values to be added ")WHERE order_id='1'

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np_order ： Table name

customer_remark Field name

where Post specified condition

8、 ... and 、mysql hold select result update Update to table , Update data from query results

Logic ： Connect two tables to get finishin The weight of is inserted into sale.

UPDATE sale
INNER JOIN (
	SELECT
		sale.FNo,
		sale.FEntryID,
		(finishin.FQty) AS qty
	FROM
		sale,
		finishin
	WHERE
		sale.FNo = finishin.FNo
	AND sale.FEntryID = finishin.FEntryID
	ORDER BY
		sale.FNo
) sale2 ON sale2.FNo = sale.FNo
AND sale2.FEntryID = sale.FEntryID
SET sale.FqtyIn = sale2.qty

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Logic ：timefinishin There are multiple identical FBillNo,FEntryID The same data , Sum by grouping qty Total weight , Become a new watch and salesorderinfo Connect tables

UPDATE salesorderinfo
INNER JOIN (
	SELECT
		salesorderinfo.FBillNo,
		salesorderinfo.FEntryID,
		(timein.FqtyIn) AS qty
	FROM
		salesorderinfo,
		(
			SELECT
				*, SUM(timefinishin.FQty) AS FqtyIn
			FROM
				timefinishin
			GROUP BY
				FBillNo,
				FEntryID
		) timein
	WHERE
		salesorderinfo.FBillNo = timein.FBillNo
	AND salesorderinfo.FEntryID = timein.FEntryID
) sale2 ON sale2.FBillNo = salesorderinfo.FBillNo
AND sale2.FEntryID = salesorderinfo.FEntryID
SET salesorderinfo.FqtyIn = sale2.qty

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Find something good ,https://httpbin.org/ This website can be used to test http request Reference resources ：

https://blog.csdn.net/qq_36823916/article/details/79403696

https://blog.csdn.net/qq5621/article/details/108098826

https://blog.csdn.net/cydbetter/article/details/82117841

https://blog.csdn.net/mary19920410/article/details/76545053

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