(SELECT 1 `a`) UNION (SELECT 2 `a`) ORDER BY `a` DESC LIMIT 1 is a perfectly valid query in MySQL and as far as I can tell the same as SELECT 1 `a` UNION SELECT 2 `a` ORDER BY `a`…
I have 2 tables: book_users and assign_book_users. they look like the image below respectively. id book_id user_id status 1 11 33 open 2 44 54 closed 3 11 98 pending 4 12 33 open 5 23 99 open 6 24…
I'm learning Python on VSCode, initially I had installed Python 3.9.2 64 bit on my Debian system, I arrived a part of the course where needed to use. The following line of code: id: str | None Then Python started…
I have two SQL queries like this for postgresql: The first query is fetching subscriptions that were never synced or that were updated recently and synced a long time ago: SELECT * FROM subscriptions WHERE (last_sync_at IS NULL OR last_sync_at…
I have two tables I want to compare data from. The query of the first table is below and it gives me 12 rows. ***** 1st Query ************ SELECT distinct a.pnr AS PNR, a.station_code as Station,a.date as Date, sum(a.allamount) as…
How can I update multiple rows in one query? UPDATE table SET col_1=col_1+5, col_2=col_2+7 WHERE id=12; UPDATE table SET col_1=col_1+2, col_2=col_2+6 WHERE id=16 ... UPDATE table SET col_1=col_1+..., col_2=col_2+... WHERE id=... How to union following queries
I have table 1 and table 2, where Table 1 is master table and Table 2 is child table. Relationship of both table has been implemented by primary key of table 1(id) with table_1_id column in table 2. I need…
UNION can be used to merge the rows of two sub-requests: SELECT column_name FROM table1 UNION SELECT column_name FROM table2; By default, MySQL's UNION is actually UNION DISTINCT, which means that the rows table1 and table2 have in common are…
I have an odd question. I have three tables all with different information but a few common columns. I want to get a sum from the tables, but I also want to know which table the data came from. I…
I need to collect data from different tables, without duplicates and with a column that collects the presence where I've found each item. So, this is my scenario: TABLEA itemId name 1 John 2 Sam TABLEB itemId name 1 John…