|
Where
|
Having
|
|
1.Without group by
clause
2. Where clause
select Row before grouping.
3. Where clause
can’t contain aggregate function.
|
1.With group by
clause
2.Having clause
select after grouping
3.Having clause
contain aggregate
Function.
|
|
Join
|
Union
|
|
1. Join the columns.
2.
Duplicate
are allowed
3.
Combine
the column based on condition.
|
1.Merge the row
2.Duplicates are
not allowed
3. Combine the
result of two select statements.
|
|
Drop
|
Delete
|
Truncate
|
|
1. Whole structure
and data will drop.
2.can’t Rollback
3.can’t use where
clause
4.All data and
structure
drop simultaneously
|
1. Structure will
not drop, data will drop.
2.can Rollback
3.can use WHERE
clause
4. Row by Row data
Delete
|
1. Structure will
not drop data will drop.
2.can’t Rollback
3.can’t use WHERE clause
4. Only all data
will drop, truncate operation drop and recreate the table.
|
|
Star schema
|
Snowflake Schema
|
|
1.
De-Normalized Data Structure
2.
Category wise Single Dimension Table
3.
More data dependency and redundancy
4.
No need to use complicated join
5.
Query Results Faster
6.
No Parent Table
7.
Simple DB Structure
|
1.
Normalized Data Structure
2.
Dimension table split into many pieces
3.
less data dependency and No redundancy
4.
Complicated Join
5.
Some delay in Query Processing
6.
It May contain Parent Table
7.
Complicated DB Structure
|
