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how to Avoid self-join in spark scala

I have a DataFrame called product_relationship_current and I’m doing a self-join to retrieve a new DataFrame like bellow: First I’m giving it an alias so I could consider them like two different dataframes: And then I’m doing a self-join to get a new dataframe: But I’m looking for anot…

table only record one character of my form field

One of my tables from pgsql has a strange behaviour like the title says. Here are some screenshots: As you can see, the name zamdam must be record in the column “nom” in pgadmin instead of recording one letter for one column, here is the sql statement + server code : It was working well until I st…

Find departments with no employees

We were given an assignment in class to provide at the minimum two different solutions to find departments, which don’t have any employees. As you can see from below I completed the task successfully. An additional solution is extra credit, which I like to get. Unfortunately, I can’t think of a th…

MySQL – Join 2 tables and count number of entries

I’m trying to join 2 tables and count the number of entries for unique variables in one of the columns. In this case I’m trying to join 2 tables – patients and trials (patients has a FK to trials) and count the number of patients that show up in each trial. This is the code i have so far: Th…

Update statement with inner join on Oracle ORA-01427

ORA-01427: single-row subquery returns more than one row ORA-06512: at “SYS.DBMS_SQL”, line 1721 I need to do update with inner join in ORACLE Answer The script you provided above is going to update all rows in the table because you do not have a where clause. If you really want to update all rows…

SQL: Flattening multiple rows in ugly data

I’m working on a fairly odd scenario in which I’ve got to compensate for a client’s database that isn’t very well-ordered. The data (example below) concerns some products that have a main serial number (serial) and between 0 and 4 additional alternate serials (alt_serial). Unfortunatel…