What is right preposition to use before a location? [duplicate]
Solution 1:
No, the preposition in isn't universal in conjunction with the verb to work. That's the answer to your question.
In, for, and at are used interchangeably in most cases.
I work {in/for/at} a bank.
is a perfectly reasonable trio of standard and idiomatic sentences. They all mean that I am employed by the bank.
If one wants to qualify one's working conditions, one needs to say more, e.g.,
I work for myself, but every day I take my notebook PC and work {in/at} the university.
I employ myself, but my working venue is a university library.
I used to work for a professor of Education. I worked at the university in his office, but I didn't work for the university; I worked strictly for him. I wouldn't say that I worked in the university in this case: it doesn't take the same usage rules as {in/at} the university library.
Prepositions are strictly native-speaker knowledge-governed. Not everyone who speaks the same dialect (national or regional) uses the same preposition as everyone else. Sometimes one has to use the preposition that makes semantic sense (if something's sitting on top of the table, one must say on the table, not by the table or under the table), and sometimes not (Let's walk {up/down} this block for a few minutes , regardless of whether the block goes uphill or downhill or the numbers ascend from 0 to 100 or descend from 100 to zero).
Context is more important that business type, and idiomatic usage for one's regional or national dialect is also important.
Solution 2:
As a guide, you work for an employer, in a department, at a location. For example, you could work for Airbus, in the finance department, at the research facility.
It can get quite fuzzy though, because there is a lot of overlap. An employer name can be used to point to both the employer and the premises, at least locally where everybody knows the name, so "I work for/at Airbus" would both work. Similarly, where a business has only one function, the employer and the 'department' overlap - "I work for/in a restaurant".
This is why you have never heard "She works for a shoe factory" but you have heard "She works for a law firm." 'Law firm' points to both the employer and the premises ("There's a law firm on the 4th floor"), but 'shoe factory' points only to the premises.