sql-update

问题 I develop an project using JPA along with Hibernate and I have two threads: Thread A: is always reading and outputs the differences Thread B: has some write operations and one transaction which is committed after finishing writing data If I delete data or insert new data from/in the database, after committing transactions from Thread B, in Thread A I see the differences, that some data was removed or added. My problem is when I update existing data: after committing, Thread A doesn't see the

问题 For MySQL, is it possible to update a field of type SET using one of the field's named values and bitwise operators? Example: Assume foo to be SET('a', 'b',...) , then the following does not work: UPDATE mytable SET foo = foo | 'a' WHERE ... Apparently, only foo = 'a' or foo = foo | 1 work. Is there any trick to get the above example working and make MySQL be aware of 'a' being not a "normal" string? I'd like to avoid magic numbers... Many thanks! 回答1: UPDATE mytable SET foo = CONCAT_WS(',',

问题 I am trying to convert following PostgreSQL query into jOOQ: UPDATE book SET amount = bat.amount FROM ( VALUES (2, 136),(5, 75) ) AS bat(book_id, amount) WHERE book.book_id = bat.book_id; VALUES inside of FROM-clause are being created from Map<Long, Integer> bookIdsAmountMap parameter and I am trying to perform that this way: class BookUtilHelper { @SuppressWarnings("unchecked") static Table<Record2<Long, Integer>> batTmp(DSLContext dsl, Map<Long, Integer> bookIdAmountMapUpdated) { Row2<Long

问题 I'm trying to update the latest record where name is John ( John has multiple records but different ID) but I seem to be in a bind. What's wrong with my query? UPDATE messages_tbl SET is_unread=1 WHERE ReceiveTime = (SELECT MAX(ReceiveTime) FROM messages_tbl WHERE name='John') Is there a better way to do something like this? 回答1: You can join both and perform update based on the condition. UPDATE messages a INNER JOIN ( SELECT name , MAX(ReceiveTime) max_time FROM messages GROUP BY name ) b

问题 I'm trying to update the latest record where name is John ( John has multiple records but different ID) but I seem to be in a bind. What's wrong with my query? UPDATE messages_tbl SET is_unread=1 WHERE ReceiveTime = (SELECT MAX(ReceiveTime) FROM messages_tbl WHERE name='John') Is there a better way to do something like this? 回答1: You can join both and perform update based on the condition. UPDATE messages a INNER JOIN ( SELECT name , MAX(ReceiveTime) max_time FROM messages GROUP BY name ) b

问题 I write the code to scrap car info(title, make, model, transmission, year, price) data from ebay.com and save in the mysql, I want if all row's(title, make, model, ...) item's is be similar to another row then avoid to insert this data to the mysql, *only when all row's item be similar(because some title is simialr or some model or...) code : import requests from bs4 import BeautifulSoup import re import mysql.connector conn = mysql.connector.connect(user='root', password='******', host='127

问题 I have the data ready to Insert into my Production table however the ID column is NULL and that needs to be pre-populated with the IDs prior to Insert. I have these IDs in another Temp Table... all I want is to simply apply these IDs to the records in my Temp Table. For example... Say I have 10 records all simply needing IDs. I have in another temp table exactly 10 IDs... they simply need to be applied to my 10 records in my 'Ready to INSERT' Temp Table. I worked in Oracle for about 9 years

问题 I import an SQL file to my database but there is something wrong. All punctuation at the end of a sentence/phrase have extra space. Example: This is a sentence . This , as you can see , is a problem . Do it ! Should be: This is a sentence. This, as you can see, is a problem. Do it! To correct, I am planning to run SQL commands on phpMyAdmin in this context UPDATE book SET content = REPLACE(content,' .','.'); UPDATE book SET content = REPLACE(content,' ,',','); UPDATE book SET content =

问题 I have a problem when accessing values in UPDATE-FROM clause in jOOQ. I want to convert following PostgreSQL query: UPDATE book SET amount = bat.amount FROM ( VALUES (2, 136),(5, 75) ) AS bat(book_id, amount) WHERE book.book_id = bat.book_id; VALUES inside of FROM-clause are being created from Map bookIdsAmountMap parameter and I am trying to perform that this way: This is what I have done in my code so far (by Lukas Eder answer suggestion) made in this question: Row2<Long,Integer> array[] =

问题 I have a table called productLocation , and its data structure as follows, SQLFiddle +--------------+-------------+-----------+ | FkLocationId | FkProductId | SortValue | +--------------+-------------+-----------+ | 1 | 100 | 0 | +--------------+-------------+-----------+ | 1 | 101 | 0 | +--------------+-------------+-----------+ | 1 | 102 | 0 | +--------------+-------------+-----------+ | 1 | 103 | 2 | +--------------+-------------+-----------+ | 1 | 104 | 1 | +--------------+-------------+-