Home/ Questions/Q 14407
Next
In Process

askthedev.com Latest Questions

Asked: 2024-09-27T02:19:34+05:30 In:

how to write not equal in sql

I’m currently working on a SQL project and I’ve hit a bit of a roadblock. I’m trying to filter my query results based on certain criteria, but I need to exclude specific values from my results. I remember learning that comparisons are a key part of SQL, but I’m unsure about how to specifically indicate ‘not equal’ when formulating my queries.

I’ve seen some examples online, and it seems that there are different operators that can be used for this purpose, but I can’t remember which one is the standard or most widely accepted. Should I use `<>` or is there another option like `!=`? Additionally, I’m a bit confused about how this would fit into a larger query—like if I’m using it in a `WHERE` clause.

For instance, if I’m trying to select all records from a table where the status is not equal to ‘inactive’, what would that look like in SQL? It feels like a simple issue, but I just want to make sure I’m using the correct syntax. Any guidance on how to effectively use ‘not equal’ in SQL would be greatly appreciated!

Share

    Leave an answer

    You must login to add an answer.

    Need An Account,

    2 Answers

    1. Writing ‘Not Equal’ in SQL

      So, you wanna know how to write ‘not equal’ in SQL? Well, it’s actually pretty simple!

      In SQL, you can use two main ways to say ‘not equal’:

      • <> – This is the most common one! Like, if you want to check that something is not equal to something else, you can just write:
        • SELECT * FROM table_name WHERE column_name <> 'value';
      • != – This one works too, and it’s actually pretty popular in some databases!
        • SELECT * FROM table_name WHERE column_name != 'value';

      Both of these will give you rows where the column_name is NOT equal to 'value'. Easy peasy!

      Just keep in mind that the exact way to do stuff might depend on the database system you’re using (like MySQL, PostgreSQL, etc.), but generally, they support these two ways!

      So go ahead and try it out! Happy querying!


    2. To express “not equal” in SQL, there are primarily two operators utilized: `<>` and `!=`. Although both perform the same function in SQL, `<>` is the standard and more widely accepted notation, while `!=` is considered a non-standard alternative that may be found in various SQL dialects. When constructing a query, you can employ these operators to filter records that do not match a specific value. For instance, to retrieve records from a table named `employees` where the job title is not ‘Manager’, you can write the query as: `SELECT * FROM employees WHERE job_title <> ‘Manager’;` or `SELECT * FROM employees WHERE job_title != ‘Manager’;`. In practice, the former is generally preferred for its adherence to SQL standards.

      In addition to `<>` and `!=`, employing these operators can extend to various SQL clauses, including `WHERE`, `HAVING`, and even in conditions of `JOIN` statements. It’s crucial to consider the context in which you’re using these operators; while they are effective for comparing scalar values, when dealing with NULLs, it’s necessary to handle such cases separately, since comparisons with NULL will yield unknown outcomes. To include NULL values in your conditions, you can integrate the `IS NOT NULL` clause. For example: `SELECT * FROM employees WHERE job_title IS NOT NULL AND job_title <> ‘Manager’;`. This ensures your query retrieves all relevant records while maintaining the desired exclusion criteria.

    Related Questions