MySQL - UPDATE Query With LIMIT
Solution 1:
If you want to update multiple rows using limit in MySQL you can use this construct:
UPDATE table_name SET name='test'
WHERE id IN (
SELECT id FROM (
SELECT id FROM table_name
ORDER BY id ASC
LIMIT 0, 10
) tmp
)
Solution 2:
When dealing with null, =
does not match the null values. You can use IS NULL
or IS NOT NULL
UPDATE `smartmeter_usage`.`users_reporting`
SET panel_id = 3 WHERE panel_id IS NULL
LIMIT
can be used with UPDATE
but with the row count
only
Solution 3:
I would suggest a two step query
I'm assuming you have an autoincrementing primary key because you say your PK is (max+1) which sounds like the definition of an autioincrementing key.
I'm calling the PK id
, substitute with whatever your PK is called.
1 - figure out the primary key number for column 1000.
SELECT @id:= id FROM smartmeter_usage LIMIT 1 OFFSET 1000
2 - update the table.
UPDATE smartmeter_usage.users_reporting SET panel_id = 3
WHERE panel_id IS NULL AND id >= @id
ORDER BY id
LIMIT 1000
Please test to see if I didn't make an off-by-one error; you may need to add or subtract 1 somewhere.
Solution 4:
In addition to the nested approach above, you can accomplish the application of theLIMIT
using JOIN
on the same table:
UPDATE `table_name`
INNER JOIN (SELECT `id` from `table_name` order by `id` limit 0,100) as t2 using (`id`)
SET `name` = 'test'
In my experience the mysql query optimizer is happier with this structure.
Solution 5:
UPDATE `smartmeter_usage`.`users_reporting` SET panel_id = 3 LIMIT 1001, 1000
This query is not correct (or at least i don't know a possible way to use limit in UPDATE queries), you should put a where
condition on you primary key (this assumes you have an auto_increment column as your primary key, if not provide more details):
UPDATE `smartmeter_usage`.`users_reporting` SET panel_id = 3 WHERE primary_key BETWEEN 1001 AND 2000
For the second query you must use IS
UPDATE `smartmeter_usage`.`users_reporting` SET panel_id = 3 WHERE panel_id is null
EDIT - if your primary_key is a column named MAX+1 you query should be (with backticks as stated correctly in the comment):
UPDATE `smartmeter_usage`.`users_reporting` SET panel_id = 3 WHERE `MAX+1` BETWEEN 1001 AND 2000
To update the rows with MAX+1 from 1001 TO 2000 (including 1001 and 2000)
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