This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Update row with data from another row in the same table
I have created table as
create table myTable (id INT, myData varchar(20));
And I have values as
insert into myTable VALUES
(1, 'Value 1'),
(2, 'Value 2'),
(3, 'Value 3');
Now I insert row as
insert into myTable (id) values (4);
Now I want to insert data for id 4. Value for id 4 is same as id 3. SO I believe I need to use UPDATE statement.
I tried with below, however it won't work.
update myTable SET myData=(select myData FROM myTable WHERE id=3) WHERE id=4;
Please let me know what need to be done.
Demo at sqlfiddle
NOTE
Actually I have myData type as MEDIUMBLOB, however for demo purpose I used varchar.
In MySQL you can't update the same table your are selecting from. That leads to the error
You can't specify target table 'myTable' for update in FROM clause
But you can trick MySQL by creating a temp table
update myTable
SET myData=(select * from (select myData FROM myTable WHERE id=3) x)
WHERE id=4;
Can you not just use an inner join with aliased tables like this:
update myTable left_table
inner join myTable right_table ON right_table.id = 3
set left_table.myData = right_table.myData
where left_table.id = 4;
Updated fiddle
Related
I am trying to write a query to insert values in table2 with reference to table1 using a foreign key.table2 columns are (quesid(primary key/auto-increment), ques,ques_desc). There is another table table1 its primary key is foreign key which is also AUTO INCREMENT. So using that i was trying to insert values.
I have written below query:
insert into users_ques values("What is JAVA","Please SHare the details")
from users WHERE quesid = 1;
mysql is giving me error at WHERE (where is not valid at this position).
please help me so that i can sucessfully write this query.
The correct way to use select for insert
insert into users_ques (column1,column2)
select column1,column2
from users
where quesid = 1;
That is not a valid MySQL INSERT syntax. You either do:
INSERT INTO users_ques
VALUES ("What is JAVA","Please SHare the details");
OR
INSERT INTO users_ques
SELECT "What is JAVA","Please SHare the details" FROM users WHERE quesid = 1;
The way you're doing it now is just combining the two method together.
Demo fiddle
This question already has answers here:
MySQL: Insert record if not exists in table [duplicate]
(16 answers)
Closed 7 years ago.
I have two tables event and guest and an eventGuest table that joins them together and has some information about the guest (like if they attended etc) and am trying to insert into the eventGuest table without creating a duplicate sort of like:
insert into eventGuest(eventID, GuestID, attended)
values(iEventID, iGuestID, bAttended)
where (select count(*) from eventGuest where eventID = iEventID and guestID = iGuestID) = 0
Copy one table data to another :-
INSERT INTO TARGET_TABLE (`col1`,`col2`) SELECT `col1`,`col2` FROM SOURCE_TABLE;
You should use INSERT INTO ... SELECT if you want to insert values from a table into another:
INSERT INTO eventGuest(eventID, GuestID, attended)
SELECT iEventID, iGuestID, bAttended
FROM Anothertable t
where NOT EXIST(select 1
from eventGuest e
where e.eventID = t.iEventID
and e.guestID = t.iGuestID);
Or, if you want to insert into the same table if the values of eventid and iGuestid doesn't exist, you can do this:
INSERT INTO eventGuest(eventID, GuestID, attended)
SELECT *
FROM ( SELECT 'eventid', 'guestid', 'somevalue' ) AS t
WHERE NOT EXISTS (
SELECT 1 FROM eventGuest e
WHERE e.eventID ='eventid'
and e.guestID = 'guestid'
) LIMIT 1;
Please do add a unique constraint in the eventGuest table for both eventid and guestid and use INSERT IGNORE or REPLACE command to insert the new data.
This question already has an answer here:
how to fetch data from two tables in mysql?
(1 answer)
Closed 8 years ago.
I have to find out the output as name of student with highest marks? My both tables are-
CREATE TABLE student(Fields_ID INT, Name VARCHAR(20));
INSERT INTO student(Fields_ID,Name) VALUES(30,'JYOTI');
INSERT INTO student(Fields_ID,Name) VALUES(31,'KIRTI');
INSERT INTO student(Fields_ID,Name) VALUES(32,'YOGITA');
INSERT INTO student(Fields_ID,Name) VALUES(33,'RASHMI');
INSERT INTO student(Fields_ID,Name) VALUES(34,'NUPUR');
SELECT * FROM student;
CREATE TABLE Marks(Fields_ID INT, Student_ID INT NOT NULL,marks INT NOT NULL);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (30,40,100);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (31,41,88);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (32,42,72);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (33,43,33);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (34,44,15);
SELECT * FROM Marks;
I was trying to return the required out from the following code but it does not return same. Any idea why it is not returning the right values.I am a beginner in MySql so I am unable to find out the problem.
SELECT student.name,Marks.marks
FROM student INNER JOIN Marks
ON student.Fields_ID=Marks.Fields_ID;
SELECT student.name,Marks.marks
FROM student INNER JOIN Marks
ON student.Fields_ID=Marks.Fields_ID
where Marks.marks = (select max(marks) from Marks);
SELECT student.name,Marks.marks
FROM student
INNER JOIN Marks
ON student.Fields_ID=Marks.Student_ID
ORDER BY Marks.marks DESC
LIMIT 1
SELECT student.name,Marks.marks
FROM student INNER JOIN Marks
ON student.Fields_ID=Marks.Fields_ID
ORDER by marks DESC;
http://sqlfiddle.com/#!2/a5324/11
This is desired output?
EDIT: add LIMIT 1 to query if you want JUST ONE result.
This question already has an answer here:
how to fetch data from two tables in mysql?
(1 answer)
Closed 8 years ago.
I have to find out the output as name of students who have secured more than 70? My both tables are-
CREATE TABLE student(Fields_ID INT, Name VARCHAR(20));
INSERT INTO student(Fields_ID,Name) VALUES(30,'JYOTI');
INSERT INTO student(Fields_ID,Name) VALUES(31,'KIRTI');
INSERT INTO student(Fields_ID,Name) VALUES(32,'YOGITA');
INSERT INTO student(Fields_ID,Name) VALUES(33,'RASHMI');
INSERT INTO student(Fields_ID,Name) VALUES(34,'NUPUR');
SELECT * FROM student;
CREATE TABLE Marks(Fields_ID INT, Student_ID INT NOT NULL,marks INT NOT NULL);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (30,40,100);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (31,41,88);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (32,42,72);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (33,43,33);
INSERT INTO Marks(Fields_ID,Student_ID,Marks) VALUES (34,44,15);
SELECT * FROM Marks;
I was trying to return the required out from the following code but i was unable to form the logic. Any idea how to do it.I am a beginner in MySql so I am unable to find out the problem.
SELECT student.name,(select (marks>70) from marks)
From Student INNER JOIN marks
ON student.Fields_ID = marks.Fields_ID
GROUP BY student.name;
You can check conditions for groups with the having clause.. Use having to check if the sum of the marks reached your limit for every student.
SELECT student.name
From Student
INNER JOIN marks ON student.Fields_ID = marks.Fields_ID
GROUP BY student.name
HAVING sum(marks) > 70
This question already has answers here:
How to do INSERT into a table records extracted from another table
(9 answers)
Closed 3 years ago.
As the title says, I am trying to insert into one table selecting values from another table and some default values.
INSERT INTO def (catid, title, page, publish)
(SELECT catid, title from abc),'page','yes')
INSERT INTO def (catid, title, page, publish)
VALUES
((SELECT catid, title from abc),'page','yes'))
The first query gives a mysql error and the second one gives column count does not match.
What do I need to do?
You simply have to do:
INSERT INTO def (catid, title, page, publish)
SELECT catid, title, 'page','yes' from `abc`
If you want to insert all the columns then
insert into def select * from abc;
here the number of columns in def should be equal to abc.
if you want to insert the subsets of columns then
insert into def (col1,col2, col3 ) select scol1,scol2,scol3 from abc;
if you want to insert some hardcorded values then
insert into def (col1, col2,col3) select 'hardcoded value',scol2, scol3 from abc;
INSERT INTO def (field_1, field_2, field3)
VALUES
('$field_1', (SELECT id_user from user_table where name = 'jhon'), '$field3')
If you you want to copy a sub-set of the source table you can do:
INSERT INTO def (field_1, field_2, field3)
SELECT other_field_1, other_field_2, other_field_3 from `abc`
or to copy ALL fields from the source table to destination table you can do more simply:
INSERT INTO def
SELECT * from `abc`
With MySQL if you are inserting into a table that has a auto increment primary key and you want to use a built-in MySQL function such as NOW() then you can do something like this:
INSERT INTO course_payment
SELECT NULL, order_id, payment_gateway, total_amt, charge_amt, refund_amt, NOW()
FROM orders ORDER BY order_id DESC LIMIT 10;