QueryFailedError:` Duplicate column name ' error caused by a bad alias naming

Issue type:

[ ] question [x] bug report [ ] feature request [ ] documentation issue

Database system/driver: all

TypeORM version: [x] latest [] @next [ ] 0.x.x (or put your version here)

Steps to reproduce or a small repository showing the problem

Let’s take a simple example with 2 tables with a OneToOne cardinality: article(#id, category_id., ..) and article_category(#id, ...). So one article has only one category.

a findOne will generate alias naming like that :

`Article`.`category_id` AS `Article_category_id`,
`Article_category`.`id` AS `Article_category_id`,

And so an error:

QueryFailedError:` Duplicate column name 'Article_category_id' 

_Originally posted by @mohamed-badaoui in https://github.com/typeorm/typeorm/issues/1969#issuecomment-687055194_

[jcuna]

This is a pretty annoying bug, in my case, if I remove {eager: true} from child relationship’s inverseSide and instead specify relations: ['child'] on the findOne method, the problem goes away. It seems to use different name strategy. I have also noticed that this behavior is different on different database drivers. For instance, it currently only happens when I’m using a Mysql database, which sucks because my integration tests all pass since I’m using Sqlite for them.

[luisgarciaalanis]

I am seeing the same ContactEntity.organization_id AS ContactEntity_organization_id, ContactEntity_organization.id AS ContactEntity_organization_id,

@ManyToOne(() => OrganizationEntity, (org) => org.id, { eager: true })
@JoinColumn({ name: 'organization_id' })
organization!: OrganizationEntity;

“typeorm”: “^0.2.29”,

@Entity('organization')
export class OrganizationEntity extends BaseEntity {
    @PrimaryGeneratedColumn()
    id!: number;