Optimize Your SQL Queries Based on The Query Optimization

INTRODUCTION

The Sql statement is used to retrieve data from the database. We can get the same result by typing different sql queries. When performance is considered, it is important to use the best query. So you have to tune the query based on requirement. Here is a list of questions we re-use and how these sql questions can be optimized for better performance.

1)  Create Indexes

To improve the performance of your SQL queries, you can learn how to index properly. Indexes allow quick access to the database in normal situations. Database novice often find indexes mysterious or difficult. They are not either indexes or they try to index everything. Of course, none of these approaches are right. Without any index, your query is likely to be slow. If you index everything, then your updates and inserted triggers will be inefficient.

2) Define fields to retrieve the data that you need instead of SELECT *

While running investigator queries, many SQL developers use SELECT * ("Select All") as a shorthand to ask for all the available data from a table. However, if there are many fields and many rows in a table, then doing this does the database resources to ask for a lot of unnecessary data.

3) Apply WHERE instead of HAVING to Define Filters

Similarly, for the above-mentioned concept, the goal of a skilled query is to draw only necessary records from the database. According to the SQL Order of Operations, HAVING statement is calculated after the WHERE statement. If the intention is to filter a query based on conditions, the WHERE statement is more efficient.

4) Apply Wildcards at the End of a Phrase Only

While searching for plain text data such as cities or names, wildcards make the most extensive search possible. However, the most comprehensive search is also the most inefficient search. When a leading wildcard is used, especially in the combination of one final wildcard, the database is used to find all records for any match anywhere within the selected area.

5) Apply LIMIT to Sample Query Results

Before running a query for the first time, make sure that the results will be desirable and meaningful using the LIMIT statement. (In some DBMS systems, the top word is used with each other with LIMIT.) The LIMIT statement gives the number of specified records only. Using a LIMIT statement prevents taxing the production database with a large query, only to find out the query needs editing or refining.

You have now learned about optimizing the sql queries. If you'd like to learn more about them, please visit the following links: https://www.ibm.com/support/knowledgecenter/en/SSZLC2_7.0.0/com.ibm.commerce.developer.soa.doc/refs/rsdperformanceworkspaces.htm