Are SQL Queries Case Sensitive? (2024)

When we talk about SQL (Structured Query Language), a common question is whether SQL queries pay attention to capitalization, or in simpler terms, are they “picky” about uppercase and lowercase letters? Let’s dive into this aspect and clear up any confusion.

In SQL, when it comes to the words used for commands and operations (like SELECT, FROM, WHERE), you can write them in all uppercase, all lowercase, or even a mix of both. The database system doesn’t really care about capitalization here. For instance, these two queries mean the same thing and will give you the same results:

SELECT * FROM Table1 WHERE column1 = 'value';

select * from table1 where column1 = 'value';

You can style your queries as you prefer without affecting their functionality.

However, things can be different regarding the actual data you’re working with (like the content in your columns) and the names you give to tables or columns.

• Data Sensitivity: The data in columns is usually sensitive to capitalization. So, by default, ‘JohnDoe’ and ‘johndoe’ would be seen as different values.
• Identifier Sensitivity: Identifiers like table and column names can behave differently depending on the database system. Some might treat them as case-sensitive, meaning “MyTable” and “mytable” would be considered distinct. Others might ignore the case, treating them as the same.

The case sensitivity of identifiers such as table and column names varies based on the DBMS. In some systems like PostgreSQL, identifiers are case-sensitive unless double-quoted. For instance:

SELECT "ColumnName" FROM "MyTable";

In contrast, other systems like MySQL typically treat identifiers as case-insensitive unless specific configurations are in place to make them case-sensitive.