One of the chair attributes of God is His omniscience.
It's a word comprising two parts.
The first part, 'omni', means 'all', and second part, 'science', relate to knowledge. That means He is an omniscient God who knows everything you say, everything you think, and everything you do.
The story is told of a wealthy grandfather who had a hearing aid fitted. When he went for a routine check-up, his doctor commented, 'Your family must be happy to know that now you can hear.' The grandfather said, 'Actually, I haven't told them about the hearing aid. I just did around and listen to their conversations--and I have changed my will twice!'
God wants to bless you, but sin and disobedience can keep that from happening. When David commited adultery with bethseba, he tried to conceal it. But God exposed him. In God's eyes the only thing that is worse than sin is your unwillingness to own up to it.
Finally, David came clean and prayed, 'Against You, You only, have I sinned, and done this evil in Your sight...'(Psalms 51:4).
Then he added, 'Purge me with hyssop; and I shall be clean; wash me, and I shall be whiter than snow' (Psalms 51:7).
Note two important words: 'hyssop', which spoke of branch dipped in blood during passover, and 'wash'.
David needed spiritual bath and God gave him one. The fact is, God knows your 'every work...whether good or evil', and no mater how badly you've failed, he will cleanse you, forgive you, and restore your joy.

Does "god" know everything?

Yeah....I know.