## DML (Data Manipulation Language) data manipulation language
- Insert data: insert
- Modify the data: update
- Delete the data: delete
## DML (Data Manipulation Language) data manipulation language
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#### insert statement
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/ *
One way:
Syntax:
INSERT INTO table name (column names ...) values ( value ...)
Note: the column must not be null insert data, can be inserted as null null column, you can not write this column
* /
the SELECT * from t_student;
# 1 insert a data in the student table.
iNSERT iNTO t_student (name, age, score) values ( 'Keven', 19,66);
# 2 order of columns may be switched
insert into t_student (score, name, age) values (93, 'Semi', 17);
# 3 if the column name is omitted, the default is all columns
insert into t_student values (26, ' Hellen', 17,87, null);
# 4 can be inserted into a plurality of data
insert into t_student (name, age, score) values ( 'Voli', 17,76), ( 'Wuje', 19,64);
/ *
Second way:
Syntax:
INSERT INTO table name
set name = value column, column name = value, ...
* /
# 1 to insert a table in the student data.
INSERT INTO t_student
set name = 'SANZI', =. 17 Age , score = 81;
/ *
Way a support insert more than one row, second approach does not support the
way a child can support queries, do not support the second approach
*/
## DML (Data Manipulation Language) data manipulation language
############
#### modification statements
############
/ *
record table 1. amendments
syntax: Update table
set value = column, column = value, ...
the WHERE filter criteria
2. modify the record of multi-table [understand]
syntax:
SQL99 syntax:
Update table 1 alias
inner | left | right join aliases in table 2
on the connection conditions
set column = value, ...
the WHERE screening condition
# 1 . Review student id = 29 data
Update t_student
SET name = 'Kulen', Age = 18 is, Score = 82
WHERE id = 29;
## DML (Data Manipulation Language) data manipulation language
############
#### deleted the statement
############
/ *
Syntax:
Method 1:
Delete single table
delete from the table where the filter criteria
delete multiple tables [understand]
sql92 syntax:
Alias delete Table 1, Table 2 alias
from Table 1 alias Table 2 alias
where the join condition
and filtering conditions
sql99 syntax:
alias delete table 1, table 2 alias
from table 1 alias
inner | left | right join in table 2 aliases
on the join condition
where the filter conditions
Second way:
TRUNCATE the table table (delete all the data in the table, not added the WHERE)
* /
. # 1 student information deleted id = 16
delete from t_student where id = 26;
# 2 Delete player's team id = 1 is
the DELETE T the FROM P t_player
the INNER the JOIN
t_team T = the ON p.tid t.id
the WHERE
p.id = 1;
# 3 Delete id = 1 and the player's team the player
the DELETE T P the FROM P t_player
the INNER the JOIN
t_team T = the ON p.tid t.id
the WHERE
p.id = 1;
# 4 Clear rangdom Table
truncate table random;
