Top "Left-join" questions

A left join is an outer join which generates a result that contains all the records of the "left" table even when there are no matching records in other tables taking part in the join.

MySQL left outer join with where clause - return unmatched rows

I have two tables: pq and pe. I am trying to LEFT OUTER JOIN left table (pq) on right table (…

mysql sql join left-join
error : subquery must return only one column

I am getting the error subquery must return only one column when I try to run the following query: SELECT …

sql postgresql join left-join cross-join
Difference between left join and *= in Sybase ASE 15

I need help to understand this matter, what's the difference between the 2 queries below, all I know that they don't …

sql left-join sap-ase
dplyr join define NA values

Can I define a "fill" value for NA in dplyr join? For example in the join define that all NA …

r left-join dplyr na
MySQL Left Join + Min

Seemingly simple MySQL question, but I've never had to do this before.. I have two tables, items and prices, with …

mysql group-by left-join greatest-n-per-group min
PostgreSQL LEFT OUTER JOIN query syntax

Lets say I have a table1: id name ------------- 1 "one" 2 "two" 3 "three" And a table2 with a foreign key to …

sql postgresql left-join cross-join
Postgres: left join with order by and limit 1

I have the situation: Table1 has a list of companies. Table2 has a list of addresses. Table3 is a N …

postgresql sql-order-by left-join foreign-key-relationship duplicate-removal
Help with a WHERE on a LEFT JOIN SQL Query

I'm trying to construct a query that will include a column indicating whether or not a user has downloaded a …

sql join left-join
Find difference between two big tables in PostgreSQL

I have two similar tables in Postgres with just one 32-byte latin field (simple md5 hash). Both tables have ~30,000,000 rows. …

sql postgresql left-join exists full-outer-join
What are some good examples where SQL's OUTER JOIN is used?

I often get asked the questions in an interview that "what is an outer join in SQL"? While it can …

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