In some SQL implementations (like PostgreSQL), if you double quote a string it’ll interpret it as a column name:

smiling stick figure with short curly hair:

SELECT * FROM cats
WHERE name "ms piggy" ;

postgres:

error: column "ms piggy"
does not exist

person, thinking: right, I need to use single quotes

Here’s a table explaining what different quotes mean in different SQL databases. “Identifier” means a column name or table name.

Sometimes table names have special characters like spaces in them so it’s useful to be able to quote them.

person: I always use single quotes for strings in SQL queries! It keeps me (and others!) from getting confused.