What is columnar table in Teradata best example

What is columnar table in Teradata best example
#What is columnar table in Teradata best example:
What is columnar table in Teradata?

Let me give an example.

Create table samples.test_1(name varchar (10), id integer )
no primary index;

This table we also call it as NOPI table.

Two rules for columnar table.
  • Table must be multiset table
  • It should be NOPI table
Additional Points on columnar tables:
  • Columnar Tables allow Columns to be Partitioned.
  • An AMP still holds the entire row, but partitions vertically.
  • Columns are placed inside their own individual Container.

Comments

Post a Comment

Popular posts from this blog

SQL for Quantile Function in Teradata

Image
A Quantile is used to divide rows into a number of categories or grouping of roughly the same number of rows in each group. Quantile Function The percentile is the QUANTILE most commonly used in business. This means that the request is based on a value of 100 for the number of partitions SELECT Product_ID1, Sales_Date1, Daily_Sales1 ,QUANTILE(100, Daily_Sales1 ) AS "Quantile1" FROM Sales_Table WHERE Product_ID1 < 3000 AND Sales_Date1 > 1000930 ; The calculation is percentile for every row in the Sales table on Daily sales.
Read more

All You Need NULL Value Functions

Image
The below are the Null value functions in Tearadata. One is "NVL" and another one is "NVL2". These two functions are part of Teradata SQL . NVL -The NVL function replace null value with a string or numeric value. This is the functionality is same as Teradata function NULLIF. It requires two arguments. If the value is not null, it will not do anything. The best SQL Null functions  NVL function:  SELECT NVL (NULL,'USA'), NVL('SPAIN','USA'); ----------- USA SPAIN Also Read: Top 70 Teradata Interview Questions The NVL2 function : Returns one of two specified values (arguments#2 and Arguments#3) based on weather the first arguments in NULL or not. It requires three arguments. The rule is as follows: If expression 1 is not null, expression 2 is returned If expression 1 is null, expression 3 is returned The best NVL2 example SELECT NVL2(NULL,'FRANCE','SPAIN'), NVL2('ENGLAND','FRANCE','SPAIN...
Read more

Teradata Quick refresher for most popular Utilities

Image
Teradata utilities are very important while working with SQL and in data warehousing projects. The below short and crispy definitions help you can use while attending for interviews or in your day to day work to refresh your Teradata knowledge.  Top Teradata Utilities 1# MultiLoad  Inserts, updates, deletes, or upserts rows in a Teradata table by using the MLOAD command-line utility. It can handle multiple SQL statements in a single operation. You can provide user-defined SQL for complex operations. This stage is best used for bulk updates, deletes, upserts, and complex interface operations. 2# TPump  Inserts, updates, deletes, or upserts rows in a Teradata table using the TPUMP command-line utility. It can do concurrent updates on the same table. It can handle multiple SQL statements in a single operation. You can provide user-defined SQL for complex operations. 3# FastExport  Exports data from a Teradata table by using the FEXP command-line utility. ...
Read more