Column 'mary' does not exist

问题

i'm doing a simple query here and it returns that column 'Mary' does not exist:

SELECT  telephone.telephonenumber as tel
FROM    person, telephone
WHERE   person.idperson = telephone.idperson
AND person.personname = ‘Mary’;

Can someone explain what can be happening? I don't want Mary as a column, but as a value.

Thanks in advance, Gabriel

回答1:

Use plain single quotes to delimit a string literal 'Mary' not smart quotes ‘Mary’

回答2:

Make sure that you are quoting your string correctly.

From your snippet, I'd say that's the problem here since you're using something else than simple single quotes.

来源：https://stackoverflow.com/questions/13196572/column-mary-does-not-exist