Top "Join" questions

SQL join on multiple columns in same tables

I have 2 subqueries, but I'm having trouble joining columns together from the same tables. I tried: SELECT * FROM (SELECT userid, …

sql join

Difference between left join and right join in SQL Server

I know about joins in SQL Server. For example. There are two tables Table1, Table2. Their table structures are the …

sql sql-server join left-join right-join

Difference between natural join and inner join

What is the difference between a natural join and an inner join?

sql join natural-join

pandas three-way joining multiple dataframes on columns

I have 3 CSV files. Each has the first column as the (string) names of people, while all the other columns …

python pandas join merge

SQL left join vs multiple tables on FROM line?

Most SQL dialects accept both the following queries: SELECT a.foo, b.foo FROM a, b WHERE a.x = b.…

sql syntax join

SQL join: selecting the last records in a one-to-many relationship

Suppose I have a table of customers and a table of purchases. Each purchase belongs to one customer. I want …

sql select join indexing greatest-n-per-group

Build the full path filename in Python

I need to pass a file path name to a module. How do I build the file path from a …

python join filenames

MySQL Select all columns from one table and some from another table

How do you select all the columns from one table and just some columns from another table using JOIN? In …

select mysql join

Oracle "(+)" Operator

I am checking some old SQL Statements for the purpose of documenting them and probably enhancing them. The DBMS is …

sql oracle join outer-join

INNER JOIN vs INNER JOIN (SELECT . FROM)

Is there any difference in terms of performance between these two versions of the same query? --Version 1 SELECT p.Name, …

sql sql-server join inner-join