7.2 daily study 4

1.SQL Sentence Niuke brush questions

1.

Last question yesterday , My method seems to go against the original intention of the author , Because the topic is subquery , And the method I use is linked table query , So I did it again with subquery in a few days , Subquery is to use in（） Create another query in parentheses , Result set as in Comparison set of previous elements . 

（ Subquery and self connection are not the same thing ！）

2.

This problem is to redo the right connection of division .  It is mainly about the flexible use of left-right connections and internal connections .

2. Force button brush questions

Sitting on the notes over there

3.JavaWeb Study

I finished learning as planned yesterday css part , Start today Javascript.

4. Study MySQL

Watch the video and see the sub query

see 《MySQL Must learn knowledge 》 See the second Chapter

  Here are some important content interceptions