Useful tips for everyday
Does Count calculate NULL values? COUNT(*) returns the number of items in a group. This includes NULL values and duplicates. How do I count the…
Can a materialized view be created through a database link? Materialized views through database links are not just for Oracle databases. You can create materialized…
What does MySQL Group _ concat ( ) function do? MySQL GROUP_CONCAT() function returns a string with concatenated non-NULL value from a group. Also discussed…
How do I get unique values from two columns in SQL? Select with distinct on all columns of the first query. Select with distinct on…
How do I insert a query result into a table? To create an Insert Results query Create a new query and add the table from…
What is a PDB in Oracle? A pluggable database (PDB) is a portable collection of schemas, schema objects, and nonschema objects that appears to an…
How does collation work in a SQL Server? Basically what’s going on here is that each database has its own collation which “provides sorting rules,…
What is the purpose of the PG TRGM module? The pg_trgm module provides GiST and GIN index operator classes that allow you to create an…
How does sharding work in a MongoDB cluster? MongoDB supports horizontal scaling through sharding. A MongoDB sharded cluster consists of the following components: shard: Each…
How are computed fields used in data entities? Computed field 1 Value is generated by an SQL view computed column. 2 During read, data is…