Write clear, simple, understandable code that obviously produces correct results. Set performance goals. Then measure your code's performance. If it performs adequately, move on. Only if it isn't performing well should you spend more time on it.

Feb 28, 2012 · Say that someone came up to you and said we're going to cut down the amount of SQL that we write by replacing equals with IN. The use would be both for single scalar values and lists of numbers. SE...

In oracle you have a lot of differences between IN and EXISTS, but not necessarily in SQL Server. The other thing that you have to consider is the selectivity of the column that you use. Some cases show that IN is better.

Jan 6, 2025 · Both the Equal and IN operators are used for comparison in SQL, but they serve different purposes. The = operator is used when comparing a single value to a column, whereas the IN operator is more efficient and readable when comparing a column to multiple values.

Oct 1, 2020 · In today’s blog post let us discuss Performance Comparison – BETWEEN, IN, and Operators. I recently discussed this during the Comprehensive Database Performance Health Check. Let me ask you the question first, look at the queries here and tell me which one of the queries will run the faster.

May 21, 2012 · According to BOL, an IN clause is the same as the different elements with OR constraints. SELECT ... If you only have one element, they should indeed be identical. Need an answer? No, you need a...

Dec 14, 2020 · This tip will look at the pros and cons of each method and use a repeatable methodology to determine which method will offer the fastest performance. The best part about this tip is that the performance comparison methodology can …

Apr 16, 2020 · There are multiple ways in which a sub select or lookup can be framed in a SQL statement. PostgreSQL optimizer is very smart at optimizing queries, and many of the queries can be rewritten/transformed for better performance. Let’s discuss the topic with an example, for which I am using schema created by pgbench.

Sep 22, 2022 · Hi there! I've often been asked about these operators in terms of performance, like "which is best?" I guess I could say "well, it depends..." as in so many cases. In this post I've decided to demonstrate some factors upon which it actually depends that may not be of common knowledge, so if you are…

Mar 13, 2019 · Essentially, the EXPLAIN plan using the EQUAL operator came back with a cost of 70 and the IN operator came back with 253. I assume that the "IN" would be faster and only require 1 trip to the DB vs the total cost of 280 (70 * 4) for …

I have a generic sql statement built in PHP: $sql = 'SELECT * FROM `users` WHERE `id` IN(' . implode(', ', $object_ids) . Assuming prior validity checks ( $object_ids is an array with at least 1 item and all numeric values), should I do the following instead?

Sep 11, 2023 · I recently stirred up an interesting discussion on Twitter regarding the performance difference between using “OR” and “IN” in SQL queries. The question attracted a variety of responses, both correct and incorrect. In this blog post, I’ll outline an example to clarify the correct answer. Let us discover more about OR vs IN.

Sep 12, 2023 · In a nutshell, we discovered that the performance of these two different types of SQL queries is, surprisingly, identical. This conclusion was reached by examining the statistics IO and execution plans for both queries, which were found to be the same.

Aug 21, 2012 · As to performance - depends on the distribution and indexing - test it and see. I would go for the like statement whatever given this data but would prefer to restructure. Cursors are useful if you don't know sql.

Are there any performance differences between . SELECT * FROM table WHERE id IN (42); and. SELECT * FROM table WHERE id = 42; ? The question is about just supplying a single value. The natural assumption for me is that the optimizer will treat them as equal and perform the same optimization when fetching the data. But is that correct?

Does indexed data affect query performance? means If I passed value as 1,2,3,4... in ordered form in any IN clause, can it improve query performance? and what happen in case I pass value randomly 2...

Mar 15, 2025 · A SQL client or IDE (e.g., psql, SQL Workbench, VS Code with SQL extensions) Query analysis tools (e.g., EXPLAIN, pgEXPLAIN) Links to Tools. PostgreSQL; pgEXPLAIN; SQL Workbench/J; 2. Technical Background Core Concepts and Terminology. Query Execution Plan: A plan generated by the database to execute a SQL query. It outlines the steps the ...

Nov 6, 2016 · Pattern Matching vs. Exact Matching in BigQuery. While pattern matching using LIKE operators may seem convenient, exact matching often yields better performance. Consider the following example: Original Query (Pattern Matching with regexp_contains):

May 26, 2018 · The question is: Which query runs faster – the query with the IN operator or the query with the OR operator? The answer is simple – both are equal in terms of performance. Let’s demonstrate this with a simple example using the AdventureWorks sample database:

Jun 10, 2016 · From a performance point of view you would want to use equals to make use of indexing. From a logical point of view it would be dangerous to use 'not equals'. In this scenario you could delete unexpected data.

5 days ago · Pinal Dave is an SQL Server Performance Tuning Expert and independent consultant with over 22 years of hands-on experience. He holds a Masters of Science degree and numerous database certifications. Pinal has authored 14 SQL Server database books and 88 Pluralsight courses. To freely share his knowledge and help others build their expertise, Pinal …

5 days ago · Explore the different types of databases, focusing on SQL vs. NoSQL. Understand the key SQL advantages over NoSQL, dive into an SQL databases comparison (including the difference between SQL and Oracle SQL), and choose the right database for your needs. ... But not all databases are created equal. Choosing the right one is crucial for ...

Feb 17, 2022 · Any suggestions how the 'straight' line performance of the UNION (2.5 seconds) can be emulated with a IN or JOIN clause with the small number of instances? (In this example taking 12 times longer, but in more real-world examples taking hundreds of times longer where the tables are much larger).