queryBuilder fails when using LENGTH keyword in orderBy with leftJoin and take

Issue Description

When you use LENGTH keyword inside orderBy method with leftJoin and take methods then it throws an error: "LENGTH(u" alias was not found. Maybe you forgot to join it? This is some weird behaviour that I cannot explain.

Expected Behavior

To not throw an error and to return results.

Actual Behavior

    const sortedUsers = userRepo
      .createQueryBuilder("u")
      .leftJoinAndSelect("u.permissions", "p")
      .take(2)
      .orderBy("LENGTH(u.email)", "DESC")
      .getMany();

When you only remove .leftJoinAndSelect("u.permissions", "p") then it works. When you only remove .take(2) then it works. Also when you remove only LENGTH keyword then it works with both of them. But when you use both of them and LENGTH keyword as in the example above then it throws an error: "LENGTH(u" alias was not found. Maybe you forgot to join it?

Steps to reproduce

https://github.com/mimoid-prog/typeorm-length-bug Install dependencies and npm start

My Environment

Dependency	Version
Operating System	Windows 10
Node.js version	v14.16.0
Typescript version	v4.1.3
TypeORM version	v0.2.31

Additional Context

Relevant Database Driver(s)

• postgres

Are you willing to resolve this issue by submitting a Pull Request?

• Yes, I have the time, and I know how to start.
• Yes, I have the time, but I don’t know how to start. I would need guidance.
• No, I don’t have the time, although I believe I could do it if I had the time…
• No, I don’t have the time and I wouldn’t even know how to start.

[juliengbt]

Hi!

I’ve gotten the error some weeks ago and I found a workaround if you’re interested :

const users4 = await userRepo
    .createQueryBuilder("u")
    .addSelect("LENGTH(u.name)", "nameLength")
    .leftJoinAndSelect("u.pets", "p")
    .orderBy("nameLength", "DESC")
    .take(2)
    .getMany()

Using LENGTH in addSelect and ordering by the alias doesn’t throw any error.

[mimoid-prog]

@juliengbt Thanks, your workaround works! But I needed to change the alias name because I got another error column distinctAlias.namelength does not exist. It looks like Typeorm doesn’t like camel case either 😄