Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

The limit clause (or the method DataFrame.limit if you are using Spark) is a better alternative if randomness is not critical.

PostgreSQL

SELECT id from table TABLESAMPLE BERNOULLI(10) WHERE …

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

Plan Your Work

1. Have a clear idea about what you want to do is very important, especially when you are working on an explorative project. It often saves you time to …

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

Spark SQL Guide

1. Since a Spark DataFrame is immutable, you cannot update or delete records from a physical table (e.g., a Hive table) directly using Spark DataFrame/SQL API. However …

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

Grant Permission to Users

GRANT
    priv_type [, priv_type ] ...
    ON database_table_or_view_name
    TO principal_specification [, principal_specification] ...
    [WITH GRANT OPTION];

Examples:

GRANT SELECT ON table1 TO USER user1;
GRANT SELECT ON DATABASE db1 TO USER user1 …