Comment on page
JOINs
Pinot supports JOINs, including left, right, full, semi, anti, lateral, and equi JOINs. Use JOINs to connect two table to generate a unified view, based on a related column between the tables.
Pinot 1.0 introduces support for all JOIN types. JOINs in Pinot significantly reduce query latency and simplify architecture, achieving the best performance currently available for an OLAP database.
Use JOINs to combine two tables (a left and right table) together, based on a related column between the tables, and other join filters. JOINs let you gain more insights from your data.
The inner join selects rows that have matching values in both tables.
Syntax:
SELECT myTable.column1,myTable.column2,myOtherTable.column1,....
FROM mytable INNER JOIN table2
ON table1.matching_column = myOtherTable.matching_column;
Joins a table containing user transactions with a table containing promotions shown to the users, to show the spending for every userID.
SELECT
p.userID, t.spending_val
FROM promotion AS p JOIN transaction AS t
ON p.userID = t.userID
WHERE
p.promotion_val > 10
AND t.transaction_type IN ('CASH', 'CREDIT')
AND t.transaction_epoch >= p.promotion_start_epoch
AND t.transaction_epoch < p.promotion_end_epoch
A left join returns all values from the left relation and the matched values from the right table, or appends NULL if there is no match. Also referred to as a left outer join.
Syntax:
SELECT myTable.column1,table1.column2,myOtherTable.column1,....
FROM myTable LEFT JOIN myOtherTable
ON myTable.matching_column = myOtherTable.matching_column;
A right join returns all values from the right relation and the matched values from the left relation, or appends NULL if there is no match. It is also referred to as a right outer join.
Syntax:
SELECT table1.column1,table1.column2,table2.column1,....
FROM table1
RIGHT JOIN table2
ON table1.matching_column = table2.matching_column;
A full join returns all values from both relations, appending NULL values on the side that does not have a match. It is also referred to as a full outer join.
Syntax:
SELECT table1.column1,table1.column2,table2.column1,....
FROM table1
FULL JOIN table2
ON table1.matching_column = table2.matching_column;
A cross join returns the Cartesian product of two relations. If no WHERE clause is used along with CROSS JOIN, this produces a result set that is the number of rows in the first table multiplied by the number of rows in the second table. If a WHERE clause is included with CROSS JOIN, it functions like an INNER JOIN.
Syntax:
SELECT *
FROM table1
CROSS JOIN table2;
Semi/anti-join returns rows from the first table where no matches are found in the second table. Returns one copy of each row in the first table for which no match is found.
Syntax:
SELECT myTable.column1, myOtherTable.column1
FROM myOtherTable
WHERE NOT EXISTS [ join_criteria ]
An equi join uses an equality operator to match a single or multiple column values of the relative tables.
Syntax:
SELECT *
FROM table1
JOIN table2
[ON (join_condition)]
OR
SELECT column_list
FROM table1, table2....
WHERE table1.column_name =
table2.column_name;
Pinot JOINs include the following optimizations:
- Predicate push-down to individual tables
- Indexing and pruning to reduce scanning and speeds up query processing
- Smart data layout considerations to minimize data shuffling
- Query hints for fine-tuning JOIN operations.
Last modified 2mo ago