DB2 simple command: Build table, increase and revise check

DB2 Build Table:

Create table Tab_name (
   field 1   type not   null/default value

)

Change the type or length of a field in a table:

Alter TABLE Tab_name
     alter COLUMN todolist SET DATA TYPE <DATATYPE>

simple to delete and change:

Add an article:

INSERT into Tab_name (C1,C2,C3) VALUES (",", ",")

Add multiple lines:

INSERT into Tab_name (C1,C2,C3) VALUES (', ', ', ', '), (', ', ', ', '), (' ', ' ', ', '), (', ', ', '); comma separated

Insert data from one table into another table:

Insert into TAB1 (C1,C2) 
select c1,c2 from TAB2
such as:
INSERT INTO TEACHER (id,name,age)
Select Id,name, Age from STUDENT;

Modify Update:

UPDATE Table name 
    SET field name = ' character value ', field name = value, ...
    WHERE  Condition 

Remove Delete

DELETE from table name

WHERE condition ...

Note: If there is no where condition, the data in the entire table will be deleted.

Delete Table by: Droptable tabname;

Find:

Select column from table where condition
can not add where 

Conditional expression:

This figure is from the Internet

query removes duplicate rows: keyword distinct

SELECT DISTINCT field name 1, field name 2 from table name

To find data from multiple tables:

SELECT Field name 1, field Name 2 ... from table 1, table 2

WHERE table 1. field 1= table 2. Field 2

When the field name repeats, you can alias the table and then alias the field name.

Sub-query:

SELECT Field name 1, field Name 2 ... from table 1

where field 1= (SELECT field name from table name WHERE condition)