Oracle count null and not null values in column

In this article we will post two ways of counting

SQL union and where clause

Sometimes there is a need of filtering result of a

Nice article about 10 SQL optimisations: MySQL, Oracle, SQL Server, DB2, PostgreSQL

Recently I found a very nice article explaining in great

Oracle refresh statistics on owner/table

Check is it needed update of statistics If you want

Oracle, MySQL - select max and return multiple values

A common problems in SQL are to find the data

Oracle indexes - create, rebuild, select, drop

Select all indexes by status Check indexes by status by

SQL concatenate examples

Concatenation basics * concatenation functions: * Oracle - concat * MySQL - concat