SQL statement Knowledge points

1.SELECT selection
SELECT column name from table name
SELECT * FROM table name (select all columns)
SELECT SNO from SC
SELECT * from SC

2.DISTINCT lists different values, removing duplicate
SELECT DISTINCT column name from table name
SELECT DISTINCT SNO from SC

3.ORDER by sorting the result set
The default is ascending, or ASC, and you can use DESC if you want to be descending.
SELECT SNO from SC ORDER by CNO DESC
SELECT Sno,cno from SC ORDER by CNO Desc,sno ASC

4.INSERT Insertion
INSERT table Name values (value 1, value 2 ...) ）
You can specify the inserted column INSERT INTO table_name (column 1, column 2 ...) Values (value 1, value 2 ....) ）
INSERT SC VALUES (1,2,3,4)
INSERT into SC (sno,sno,name,age) VALUES (1,2,3,4)

5.UPDATE Modifying data
UPDATE table name SET column name = new value WHERE Column name = value
UPDATE person SET FirstName = ' Theron ' WHERE LastName = ' Wilson '
UPDATE person SET firstname= ' Theron ', age= ' WHERE LastName = ' Wilson '

6.DELETE Delete
DELETE from table name hwere column name = a value
DELETE from SC WHERE name= ' Theron '
DELETE from SC