I have two tables in the same database with names table1 and table2. What I need is I have to copy selected columns from table1 and update those columns in table2 based on the ID match. What I have done is :
$sql = " UPDATE table2, table1 SET table2.column1= table1.column1
where table1.primarykey= table2.primarykey && primarykey= 1 ";
This query is not throwing any error but its not updating .I am a pure beginner in mysql field. Can anyone help me out ?
Your query has an error. The second primarykey reference needs a table alias; otherwise, it is ambiguous.
I would suggest writing the query using explicit join syntax:
UPDATE table2 JOIN
table1
ON table1.primarykey = table2.primarykey
SET table2.column1 = table1.column1
WHERE table1.primarykey = 1 ;
Because you did not catch this error. I would also suggest checking for errors when you run a SQL statement at the application layer.
You can try this:
sql_query = UPDATE table1 t1, table2 t2
SET t1.field1 = t2.field1, t1.field2 = t2.field2 WHERE t1.id = t2.id;
slight modification with subquery:
$sql = " UPDATE table2 SET table2.column1= ( SELECT table1.column1 from table1
where table1.primarykey= table2.primarykey && primarykey= 1 )";
Related
Hi I have two table one like this one:
table1
and one like this:
table2
I would like to update all the fields on the table2 column "newID" based on this rules: if (table2.ID = table1.ID_actual or table2.ID=table1.ID_old) then table2.newID = table1.newID
How can I resolve this problem ?
You need a join of the 2 tables in the UPDATE statement:
UPDATE table2 t2
INNER JOIN table1 t1 ON t2.ID IN (t1.ID_actual, t1.ID_old)
SET t2.newID = t1.newID
I have a pretty simple MySQL query to implement, but I can't figure out how...
I have two tables, T1 and T2.
What I need to do:
From T1, I retrieve an ID based on a CODE value:
SELECT id FROM T1 WHERE code = '$code';
Then I need to use this ID (so the value I just retrieved) to update a specific row in T2 (the name of the row will match the ID's value).
I was thinking about using either subqueries or user-defined variables, but no matter how I try it I can't get it done.
If you have any code snippet that can help me doing that, I would appreciate it as well!
EDIT
Just to clarify something: I don't know the name of the column that I need to update in T2, since that name will be the value I retrieve from T1.
So for example, if the ID I get from T1 is "03", it will update the column named "03" in T2.
EDIT 2
Here's a little schema of what I intend to achieve (hoping I make myself clearer, I'm sorry for the misunderstanding...)
UPDATE T2 SET COL = YOUR_VALUE
WHERE T2.ID = (SELECT id FROM T1 WHERE code = '$code')
UPDATE: If the sub query returns more than one row then you can use from IN operator
UPDATE T2 SET COL = YOUR_VALUE
WHERE T2.ID IN (SELECT id FROM T1 WHERE code = '$code')
Use an UPDATE with a JOIN:
UPDATE T2
CROSS JOIN T1
SET T2.`0` = IF(T1.id = 0, T1.someColumn, T2.`0`),
T2.`1` = IF(T1.id = 1, T1.someColumn, T2.`1`),
T2.`2` = IF(T1.id = 1, T1.someColumn, T2.`1`)
WHERE T1.code = '$code'
Replace someColumn with the column in T1 containing the value you want to put into T2.
you can update without using the subquery just using join
update t2
inner join t1 on t2.name = t1.id and t1.code ='$code'
set t2.my_col = 'my_value'
but you should not use var in your query you are at risk for sql injection take a look at you mysql driver for param_binding
UPDATE T2 SET COL = YOUR_VALUE WHERE EXISTS
(SELECT 1 FROM T1 WHERE T2.id=T2.id AND code = '$code')
You can update T2 with the next SQL if you expect at least one row from the inner query
UPDATE T2 SET COLUMN = VALUE
WHERE T2.ID IN (SELECT ID FROM T1 WHERE CODE = $code)
Otherwise, if from T1 you are sure you will get only 1 record
UPDATE T2 SET COLUMN = VALUE
WHERE T2.ID = (SELECT ID FROM T1 WHERE CODE = $code)
update table1 t1
inner join
table2 t2 on
t1.a = t2.a
set t1.b = t2.b,
t1.c = t2.c;
This code works to join 2 tables on column a. My problem is that I have about 500 columns which I want to update and am currently writing out each of the 500 columns in the code up to
t1.500 = t2.500;
This works, but it is slow and inefficient. Does anyone know how you can select * from table2 to update table1, keeping the join on t1.a = t2.a? All of the column names match exactly and am inserting all of the columns from table2. Was thinking of something like this below although I know that this is not correct. Thank you!
update table1 t1
inner join
table2 t2 on
t1.a = t2.a
set t1.* = t2.*;
I think there is no way to make update query with a wildcard in mysql. Don't know if it will properly fit to your problem, but you can try this workaround. :
DELETE FROM table2 WHERE id IN (<ids>);
Delete all the records from table2 that are satisfying given condition. And then insert the corresponding records from table1 to table2.
INSERT INTO table2
SELECT * FROM table1 WHERE id IN (<ids>);
I have got two tables. I want to update MODEL in table2 when ITEM in table1 equals ITEM in table2.
Any Ideas?
In MySQL, you do it like this
UPDATE table1 t1
INNER JOIN table2 t2
ON t1.id = t2.id
SET t1.col1 = t2.col1,
t1.col2 = t2.col2
If I understand correctly, you just want to perform an UPDATE on table2 based on, presumably, foreign keys?
If that's right, this should work:
UPDATE
table2
JOIN table1
ON table1.ITEM = table2.ITEM
SET
MODEL = 'new value';
The table declaration in an UPDATE statement is the same as is specified in a SELECT statement - so you can use any type of JOIN that fits your table/data.
Docs for UPDATE, SELECT.
If you could add an actual query attempt, or something, that might be helpful. Can you try something like the following:
UPDATE table2 JOIN table1 ON table2.ITEM = table1.ITEM SET MODEL = ?
Is this possible in mysql?
update table1
set column1 = (select column1 from table2
inner join table3
where table2.column5 = table3.column6);
Here is a a similar question for an Oracle DB.
You can do it. However, in the example you give, there's no JOIN connection between table1 and the source of the values for the update (table2 INNER JOIN table3), so the results will be somewhat unpredictable.
Your query would be something like (I'm not a MySQL expert):
UPDATE table1, table2, table3 SET table1.column1 = table2.column1
WHERE table2.column5 = table3.column6
but what I think you probably want (I'm just guessing) is something more like:
UPDATE table1, table2, table3 SET table1.column1 = table2.column1
WHERE table1.somecolumn = table3.somecolumn AND table2.column5 = table3.column6