mysql--automatically numbering, adding columns, deleting columns, inserting data, deleting data, modifying data

At the time of creation

CREATE TABLE si (

Id INT auto_increment

)

Automatic numbering, can not have more than one automatic column (can be automatically coded for you)

If you add a column to it in a S11 form (this is not the same as inserting data)

ALTER TABLE hh2 ADD COLUMN (

Adde INT,

Adder VARCHAR (11)

)

Delete the adde column inside the S11

Alter Table Table name Drop column column name ;

Change structure:

ALTER table name MODIFY The data type to which the column name is to be changed

Change the table name:

ALTER table old table name RENAME new table name

DML Statements (data manipulation statements)

1. Insert ( inserting Data )
2. UPDATE(Modify data)
3. Delete(remove data)

DQL Statement (query statement)

INSERT

Format:

CREATE TABLE Hg (

I INT,

G VARCHAR (100)

)

INSERT into Hg (i,g) VALUES (121, ' 12 ')

Attention:

1. If a column is required, take it with you.
2. Automatic numbering column not filled in, he'll get it automatically.
3. Type description: In addition to the value of no single quotation marks, the others have to add!

How to add Time:

ALTER TABLE Tab_nam ADD COLUMN (

Time1 DATETIME

)

INSERT into Tab_nam (time1) VALUES (Sysdate ())

UPDATE

Format:

UPDATE table name set column = value, column value

Entire column modification

UPDATE table name set sid=sid+1// this Sid is a numeric type

DELETE

Format:

DELETE from table name

Entire table Data Delete

Add conditions can be deleted individually

Encryption:

INSERT into Tab_nam (name1) VALUES (PASSWORD (' 5654 '))

Note The data type length, after encryption, the data will be very long

Why encrypt?

Because save a password or something, can not be seen, if not set directly see the

mysql--automatically numbering, adding columns, deleting columns, inserting data, deleting data, modifying data