Issue type:

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

Database system/driver:

[ ] cordova
[ ] mongodb
[x] mssql
[x] mysql / mariadb
[x] oracle
[x] postgres
[ ] cockroachdb
[x] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ ] latest
[ ] @next
[x] 0.2.25

It would be nice if the expression passed to where() and andWhere() methods of QueryBuilder was surrounded by parentheses.

For example, the following code

qb("User", "user")
  .where("user.deleteDate IS NULL")  // expression (A)
  .andWhere("user.name = 'foo' OR user.birthDate IS NULL"); // expression (B or C) 

currently generates the following SQL sentence:

SELECT `user`.`id`, `user`.`name`, `user`.`birthDate`, `user`.`deleteDate`
FROM `User` `user`
WHERE `user`.`deleteDate` IS NULL
AND `user`.`name` = 'foo'
OR `user`.`birthDate` IS NULL

As can be seen, the resulting WHERE clause is A and B or C. But it would make more sense if it was (A) and (B or C) - because A was passed to where() and B or C was passed to andWhere().

I know that I can achieve this result by manually including the parentheses to every where condition. But, in my opinion, adding the parentheses automagically in SQL sentence generation would be better.