I'm aware that this PR won't be accepted until I add the appropriate tests and documentation. I first want to make sure that this feature is acceptable to the core maintainers.

My apologies for not writing a separate issue for that. If you believe sql tags should not exist in TypeORM, I will understand. Although, it would be harder for other tools (such as SafeQL) to integrate with TypeORM.

Description of change

Adds a new tagged template to classes that execute raw SQL queries and return raw database results. The template takes a template string and an array of values as input and builds a SQL query using the appropriate parameter strategy based on

While SQL tags can be misleading to some people regarding SQL injections, they are, in fact, safer than splitting the query from the variables. With tagged template, you simply can't go wrong with accidently injecting unsafe values from variables due to the way of how tagged templates work.

As a plus, reading the query with the variables in place adds more clarity rather than trying to figure out what is the $23 parameter.

The new sql tag will split the templates from the expressions, parameterize the statement, and then map the statement and the variables back to the query method. (tag -> { query, variables } -> query method).

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run format to apply prettier formatting
• npm run test passes with this change
• [N/A] This pull request links relevant issues as Fixes #0000
• There are new or updated unit tests validating the change
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md