In SQL queries, when in doubt, which quotation marks should be used?

In SQL queries, single quotes are used to define string literals, which represent values such as text or dates. When you want to insert a string into a table or filter records based on matching text, it is essential to enclose that string within single quotes. For example, if you wish to find rows where the "name" column matches "John," you would write the condition as WHERE name = 'John'.

Single quotes are the standard in SQL for declaring strings, ensuring that the database interprets the enclosed text as a string rather than an identifier or command. This is consistent across many SQL databases, making it a reliable choice when forming queries. By using single quotes, you also avoid conflicts with other types of quotation marks, ensuring your SQL commands are correctly executed.

Other forms of quotation, such as double quotes, are typically used for identifiers like column and table names in databases compliant with standard SQL, but their usage can vary based on database systems. Backticks are specific to certain systems, like MySQL, for escaping identifiers. Therefore, when in doubt, using single quotes for string literals is the best practice in SQL queries.