Chapter 1
1.1 Brief History of Database
1.2 Structured Query Language
SQL query is composed of various statements, clauses and conditions
1.3 Create database
Chapter 2 Insert information
Insert data: INSERT INTO
Update data: UPDATE
Delete data: DELETE
Chapter 3 Extract information
1. SELECT statement; used to select data from the database
2. Logical operators and operator priority
3. Sort results using ORDER BY
4. Select data from multiple tables
5. Overview of NULL data
Chapter 4 Advanced Database Design
This chapter is not very understanding
Chapter 5 Operating Data
SQL Arithmetic
Function NULL Use
INSERT INTO and SELECT Statement
Chapter 6 Grouping and Aggregating Data
Another way of "summarizing data" when gathering together. Grouping is to find information about a particular record, while aggregation summarizes the information in multiple records.
COUNT() function: used to count the number of records.
SUN() function: this function adds the recorded values together.
AVG
() function: finds the average value. MAX( ), MIN() function: finds the largest among multiple records Value and minimum
Chapter 7 Selecting data from different tables
Chapter 8 Subqueries in the
SELECT list of subqueries Subqueries in the
WHERE clause
Operators
in subqueries Related subqueries Subqueries
for other statements
I won't mention them one by one when there are still very small pieces of knowledge. After this stage is completed, I will enter the next stage. Come on, find and solve problems in the process of practice.