Today's Offer - SQL Server Certification Training - Enroll at Flat 10% Off.

- SQL Server Blogs -

How to Increase the Speed of SQL Query Execution

Increase the Speed of SQL Queries

SQL (Structured Query Language) is a homogeneous programming language which is widely used for organizing relational databases, and for accomplishment of several operations on the data stored in them. To trace the beginning, it was first created and used in the 1970s, SQL is frequently used by mainly the database managers, as well as by developers who are working in the profile of writing data integration scripts. Data analysts who are looking to set up and run analytical queries also use SQL.

SQL statements can be easily used to retrieve relevant data from any database that exists. To get similar outcomes you are required to write dissimilar SQL queries. For optimum performance you need to use the queries that are not only best and faster but also efficient. Therefore, you need a SQL query tuning, which is based on the business in addition to the user requirements.

We have made a list of 17 ways that you can consider to optimize your SQL queries.

  • Use Column Names Instead of * in a SELECT Statement
  • Try not to use HAVING clause in SELECT statements
  • Avoid using UPDATE instead of CASE
  • Avoid blind re-use of Code
  • Use an IN predicate when querying an indexed column
  • Try to pull specific columns that you need
  • Do pre-stage data
  • Do delete and update process in smaller batches
  • Try to use temp tables to improve cursor performance
  • Avoid nest views
  • Try to use table-valued functions
  • Use EXISTS command instead of DISTINCT when using table joins for tables with one-to-many relationships
  • Do use stored procedures for ORMs
  • Avoid using OR in join conditions
  • Avoid writing functions on the right side of the operator you put
  • Remove any redundant mathematics
  • Do to use UNION ALL in place of UNION

SQL Server Curriculum

Use Column Names Instead of * in a SELECT Statement

By choosing only the columns that you require, you are dropping the size of the result table substantially thereby decreasing the network traffic and increasing the general performance of your query.

In the below screenshot, you can see how ‘International Journal of Scientific & Technology Research’ has very well explained the concept- Increase the Speed of SQL Query Execution

Try not to use HAVING clause in SELECT statements

The HAVING clause is generally used like a filter and that makes is quite impractical in a SELECT statement. It goes through the final result table of the query analyzing the rows that don’t even meet the HAVING condition. See the concept explained in the below screenshot Increase the Speed of SQL Query Execution

Avoid using UPDATE instead of CASE

This problem is very common, because using UPDATE has a natural flow that seems rational but it is better to use CASE. An UPDATE statement has to write twofold for every single write to the table and thus slowing your results.

Read: What Is The Difference Between Tables And Views In SQL?

Avoid blind re-use of Code

Many developers tend to copy someone else’s as it pulls the data that they need. The issue is that it pulls much more data than you actually need. Trim the code to your exact needs.

Use an IN predicate when querying an indexed column

The IN-list predicate can be used substantially for indexed recovery and also, the optimizer can sort the IN-list to match the sort sequence of the index, leading to more efficient retrieval.

See the concept explained in the below screenshot by ‘International Journal of Scientific & Technology Research’ Increase the Speed of SQL Query Execution

Try to pull specific columns that you need

It is quite easy to code all your queries with SELECT* command instead of listing the columns separately every time.

SQL Server Quiz

Do pre-stage data

If you already have a report or a procedure that can do analogous joins to large tables, it can be an advantage for you to pre-stage the data by linking the tables ahead of time and persisting them into a table.

Do delete and update process in smaller batches

It helps you increase concurrency because your database can go online quickly.

Read: Future Growth of a SQL Server Developer

Try to use temp tables to improve cursor performance

Cursor operations suffer from speed and block problem. To avoid that try to run them against a temp table.

Avoid nest views

This is because you will end up in a loop where you have views that call views that call views that call views. You will have more data retrieved than is needed.

Try to use table-valued functions

Whenever you put a scalar function in the SELECT list of the query, the function is called for each single row in the result set.

Use EXISTS command instead of DISTINCT when using table joins for tables with one-to-many relationships

The DISTINCT keyword effectively works by picking all the columns in the table then analyzesany duplicates.In its place, if you use sub query with the EXISTS keyword, you can circumvent having to return an entire table as a result.

Do use stored procedures for ORMs

Stored procedures have quite a lot of benefits. The best ones are that you’re pushing much less data across the network; the procedure call is shorter etc.

Avoid using OR in join conditions

Every time when you place an ‘OR’ in the join condition, the query will slow down by at least a factor of two.

Avoid writing functions on the right side of the operator you put

Functions or methods are utilized very frequently with their SQL queries. Rewriting the query by eliminating collective functions will escalate the performance extremely.

Read: Difference Between Stored Procedure and Function in SQL Server

SQL Server training

Remove any redundant mathematics

There will be instances where you will be performing mathematical queries within an SQL statement. They can really drag on the performance if written wrongly. So removing any preventable math in the statement will make it perform more rapidly.

Do to use UNION ALL in place of UNION

The UNION ALL statement is more rapid than UNION, as a UNION ALL statement never considers copies, and UNION statement looks for duplicates in a table irrespective of their existence.

Final Words

We hope that these tips will help you write better queries. For more insight, read our other blogs on SQL.

SQL Query Related Topic


    Janbask Training

    JanBask Training is a leading Global Online Training Provider through Live Sessions. The Live classes provide a blended approach of hands on experience along with theoretical knowledge which is driven by certified professionals.


Trending Courses

AWS

  • AWS & Fundamentals of Linux
  • Amazon Simple Storage Service
  • Elastic Compute Cloud
  • Databases Overview & Amazon Route 53

Upcoming Class

1 day 14 Nov 2019

DevOps

  • Intro to DevOps
  • GIT and Maven
  • Jenkins & Ansible
  • Docker and Cloud Computing

Upcoming Class

2 days 15 Nov 2019

Data Science

  • Data Science Introduction
  • Hadoop and Spark Overview
  • Python & Intro to R Programming
  • Machine Learning

Upcoming Class

2 days 15 Nov 2019

Hadoop

  • Architecture, HDFS & MapReduce
  • Unix Shell & Apache Pig Installation
  • HIVE Installation & User-Defined Functions
  • SQOOP & Hbase Installation

Upcoming Class

3 days 16 Nov 2019

Salesforce

  • Salesforce Configuration Introduction
  • Security & Automation Process
  • Sales & Service Cloud
  • Apex Programming, SOQL & SOSL

Upcoming Class

1 day 14 Nov 2019

QA

  • Introduction and Software Testing
  • Software Test Life Cycle
  • Automation Testing and API Testing
  • Selenium framework development using Testing

Upcoming Class

20 days 03 Dec 2019

Business Analyst

  • BA & Stakeholders Overview
  • BPMN, Requirement Elicitation
  • BA Tools & Design Documents
  • Enterprise Analysis, Agile & Scrum

Upcoming Class

2 days 15 Nov 2019

SQL Server

  • Introduction & Database Query
  • Programming, Indexes & System Functions
  • SSIS Package Development Procedures
  • SSRS Report Design

Upcoming Class

6 days 19 Nov 2019

Comments

Search Posts

Reset

Receive Latest Materials and Offers on SQL Server Course

Interviews