Like I said: spoken used when you are repeating something that you have already said. As I have already mentioned; referring back to my previous point. Like I said is much more informal than As I said, but the former isn’t ungrammatical. In formal writing, you may prefer to use as, but in speech or less formal writing like is fine.
中文释义：like I said 用来重复之前已经说过的话，意思为正如我已经提到的，回到我之前的观点，主要用于再次强调内容。相反,如果表示对方所说的话,就可以用 like you said。Like I said比As I said更加非正式，但前者不是很符合语法，在正式写作中，更倾向于用as，但在口语或不太正式的写作中，用like就可以。例句：I know, but like I said, we already have tickets.（我知道，但我说过了，我们已经有票了。）