Shulou(Shulou.com)06/01 Report--

Query

Query all columns

Select * from table name

Example:

Select * from classes

Query the specified column

You can use as to specify aliases for columns or tables

Select column 1, column 2. From table name

Example:

Select id,name from classes

Increase

Note: the primary key column grows automatically, but it needs to occupy a space when inserting all the columns, usually using 0, and the actual data shall prevail after successful insertion.

Full column insertion: the order of values corresponds to the order of fields in the table

Insert into table name values (...)

Example:

Insert into students values (0Jing Guo Jing, 1pm Mongolia, 2016-1-2')

Partial column insertion: the order of values corresponds to the column order given

The name of the insert into table (column 1.) Values (worth 1pm...)

Example:

Insert into students (name,hometown,birthday) values ('Huang Rong', 'Peach Blossom Island', '2016-3-2')

The above statement can insert one row of data into a table at a time, or multiple rows of data at a time, thus reducing communication with the database.

Full column multiple row insert: the order of values corresponds to the column order given

The insert into table name is values (...), (...).

Example:

Insert into classes values (0gramme python 1'), (0recorder python 2')

The name of the insert into table (column 1.) Values (worth 1pm), (worth 1pm...)

Example:

Insert into students (name) values ('Yang Kang'), ('Yang Guo'), ('Xiao Longnu')

Modify

Update table name set column 1 = value 1, column 2 = value 2. Where condition

Example:

Update students gender=0,hometown=' Tomb 'where id=5

Delete

Delete from table name where condition

Example:

Delete from students where id=5

Logical deletion is essentially a modification operation.

Update students set isdelete=1 where id=1

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