Day 4 I have revised some of oracle concepts

Hi Everyone Today I have revised some of the topics in oracle like cross join ,set operators like union, union all, intersect, minus I would like to define them in simple words unio means that combines the two queries into one and it eliminates the duplicates gives the result in order. Union all is used to combine two rows but it gives the duplicate result also and the result is also not sorted. Intersect means the values in first query but not there in second query Group By clause It is mainly used to group rows based on rows /columns to calculate min , sum ...for each group And also I have learned ROLLUP and cube These both are used to get the grand total and sub total but the cube will displays for each group by column and also displays he grand total. Then I revised the concept of case which works similarly as the switch case to implement if -then -else simple case when the condition is based on the equal operator. vice versa for the searched case Tomorrow I will go through the subqueries which is a great topic I Will be always looking forward for my career ...

Apr 4, 2025 - 19:35

Day 4 I have revised some of oracle concepts

Hi Everyone Today I have revised some of the topics in oracle like cross join ,set operators like union, union all, intersect, minus
I would like to define them in simple words
unio means that combines the two queries into one and it eliminates the duplicates gives the result in order.
Union all is used to combine two rows but it gives the duplicate result also and the result is also not sorted.
Intersect means the values in first query but not there in second query
Group By clause
It is mainly used to group rows based on rows /columns to calculate min , sum ...for each group
And also I have learned ROLLUP and cube
These both are used to get the grand total and sub total
but the cube will displays for each group by column and also displays he grand total.
Then I revised the concept of case which works similarly as the switch case to implement if -then -else
simple case
when the condition is based on the equal operator. vice versa for the searched case
Tomorrow I will go through the subqueries which is a great topic
I Will be always looking forward for my career ...