There are two types of mixed conditional sentences. One of them states the present result of a past condition and the other state the past result of a present or continuing condition.

Present result of a past condition

Here we use a past perfect in the if-clause and would + infinitive in the main clause.

• If I had accepted that job I would be a millionaire now.
• If I had married him I would live happy now.

In these sentences the time is past in the If-clause and present in the main clause. They refer to an unreal past condition and its probable result in the present.

Past result of a present or continuing condition

Here we use a simple past in the If clause and would have + past participle in the main clause.

• If I didn’t love him I wouldn’t have married him. (= I love him and that is why I married him.)
• If I were invited I would have come. (= I was not invited. Therefore I did not go)

They refer to an unreal present situation and its probable (but unreal) past result.

• If I were a good cook, I would have invited them to lunch. (= I am not a good cook so I can’t invite them to lunch.)
• If I knew English, I would have got a better job.