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mysqllimitsql-update

MySQL - UPDATE query with LIMIT

I want to update rows in my table with starting from 1001 to next 1000.

I tried with following query:

UPDATE `oltp_db`.`users` SET p_id = 3 LIMIT 1001, 1000
  1. This is giving me syntax error. Is this correct? am I doing any mistake here.
  2. Can we limit update in this way?

Also, the rows that I am trying to update are having Null value for the column p_id which is having data type INTEGER. Due to this I am not even able to update using following query:

UPDATE `oltp_db`.`users` SET p_id = 3 WHERE p_id = null
  1. Is my above query correct?
  2. What can be done to achieve this?
Solution

  • 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