Netezza

Netezza DECODE Function Syntax and Examples

Netezza supports the DECODE function and it is similar to DECODE function in other relational databases such as Oracle, SQL Server, MySQL, Redshift etc. You can use the Netezza DECODE function to implement if-then-else statement in Netezza nzsql. This command is a short-hand form of Netezza CASE function. Netezza DECODE Function Syntax DECODE (expr, expr_val1, ’expr_rep1’, expr_val2, ’expr_rep2’, expr_val3, ’expr_rep3’, ’else-expr’) ; Execution Flow: If 'expr' is equal to expr_val1 then ’expr_rep1’ is returned, if 'expr' is equal to 'expr_val2' then ’expr_rep2’ is return, if 'expr' is equal to 'expr_val3'…

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June 3, 2017
Netezza

Netezza NVL and NVL2 Functions with Examples

Netezza supports NVL and NVL2 functions. Netezza NVL Function The NVL function replaces a NULL value with a replacement string that you provide in the function. Returns the first argument if it is not null, otherwise it returns the second argument The Netezza NVL function is equivalent to the Netezza SQL coalesce function. The Function will return the non-NULL value. Note that, You cannot replace the blank value using NVL function. Some databases supports this nut Netezza does not. Syntax: NVL (exp,replacement-exp); Returns 'exp' if not null otherwise 'replacement-exp' is…

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June 3, 2017
General

Database ACID Properties and Explanation

ACID (Atomicity, Consistency, Isolation, Durability) is a set of database properties that makes sure that database transactions are processed reliably and completly. Relational databases makes sures that its transactions are completed propely as per ACID properties . Database ACID Properties Following sections explains about various database ACID properties: Atomicity In ACID properties, Atomicity requires that each and every transaction is fully completed and committed or nothing at all. If any one part of the current transaction fails, then the entire transaction fails, and the database state is left unchanged (databse…

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June 3, 2017
Netezza

Netezza SQL Identifiers

A Netezza SQL identifier is the name of a Netezza database object such as a table, column, user, group, user-defined object, and database names. Netezza supports the SQL 1999 definition for naming identifiers, and they can be up to 128 bytes in length. Read: Netezza SQL command and its usage Netezza Create user command and its Usage IBM Netezza Alter user command and its Usage Netezza Create, Drop, Rename Database Commands and Examples Netezza SQL Identifiers There are two types of Netezza SQL identifiers: regular and delimited. Netezza SQL Regular…

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June 2, 2017
Netezza

Netezza Create, Drop, Rename Database Commands and Examples

Using Netezza SQL, you can create, drop, rename and change the database owners. These are some important commands you should know if you are working as a Netezza database administrator. In this article, we will check Netezza create, drop, rename database commands and some of examples. Read: Netezza SQL Identifiers Netezza Create Database Command You can use CREATE DATABASE command to create new database in Netezza system: system(admin)=> CREATE DATABASE newdb; CREATE DATABASE Database names can be up to a maximum length of 128 bytes, system displays an error message if…

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June 2, 2017
Netezza

How to Resolve Netezza too many Concurrent Sessions issue?

If you are working on the Netezza with the heavy load on it then you might have seen the Netezza too many concurrent sessions issue when you try to connect to the Netezza system. You may get this issue while connecting to Netezza from Aginity workbench or from Putty. In this article, we will see how to resolve Netezza too many concurrent session issue. Check Netezza too many Concurrent Sessions issue To verify the concurrent sessions follow below steps: Login to Netezza either from Putty or from Aginity Workbench and…

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June 1, 2017
Netezza

How to Find Netezza Table Size?

There are two ways to identify the size of table in Netezza. One, query the Netezza system tables and get the table size. Second, use the Netezza admin tool to check table size. In this article, we will discuss on how to find Netezza table size using Netezza nzsql and Netezza admin tools. More Readings: Netezza system tables and views Netezza nzsql command and its usage How to install Aginity workbench for Netezza? How to Find Netezza Table Size? When you create a table in Netezza using nzsql, the table…

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May 31, 2017
Netezza

Netezza Derived Tables and Examples

In the real world scenario, you may derive the some column from base table and instead of creating temporary table you may use that derived query in FROM clause of the SQL statement. These types of queries are called derived tables. In this article,we will check on the Netezza derived tables.  Netezza Derived Tables A derived table is basically a subquery which is always in the FROM clause of a SQL query Statements. The reason it is called a derived table is because it essentially functions as a table as far as the entire query…

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May 28, 2017
Netezza

Netezza Identify and Kill Table Locks

Sometimes if you try to delete or truncate data from the table that is being used by the other process then session may lock the table resulting deadlock. You have to identify and kill such sessions before attempting to delete or truncate that table.In this article, we will discuss about Netezza identify and kill tables locks with an examples. Read: Netezza Table Locking and Concurrency Netezza Identify and Kill Table Locks The mail question is how to identify the locks? There are couple of options available to identify the table…

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May 26, 2017
BigData

Hadoop Hive Analytic Functions and Examples

Hadoop Hive analytic functions compute an aggregate value that is based on a group of rows. A Hadoop Hive HQL analytic function works on the group of rows and ignores the NULL in the data if you specify. Hadoop Hive analytic functions Latest Hive version includes many useful functions that can perform day to day aggregation. Note that, Hive is batch query processing engine and hence take more time to execute. Read: Apache Hive ROWNUM Pseudo Column Equivalent Hadoop Hive Date Functions and Examples Spark SQL Analytic Functions and Examples…

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May 25, 2017