MYSQL - 更新每个组的行号

Question

I am trying to update the column sip_count so that it counts the number of rows with the same sip_id as shown below. None of the things that I have tried are worth posting. How do I do this?

Table

sip_id | sip   | sip_count
--------------------------- 
 1      |  1    | 2
 1      |  1    | 2
 2      |  1    | 3
 2      |  1    | 3
 2      |  1    | 3
 4      |  1    | 2
 4      |  1    | 2
 3      |  1    | 3
 3      |  1    | 3
 3      |  1    | 3

Desired result

 sip_id | sip   | sip_count
--------------------------- 
 1      |  1    | 1
 1      |  1    | 2
 2      |  1    | 1
 2      |  1    | 2
 2      |  1    | 3
 4      |  1    | 1
 4      |  1    | 2
 3      |  1    | 1
 3      |  1    | 2
 3      |  1    | 3

Answer 1

UPDATE

Try to use variable:

SET @i:=0;
UPDATE 
    table_name 
INNER JOIN 
    (
    SELECT 
        table_name.primary_key, 
        table_name.sip_id, 
        @i:=IF(@i > b.count, 1, @i+1) AS count 
    FROM table_name 
    INNER JOIN 
        (
          SELECT 
            sip_id, 
            COUNT(sip_count) AS count 
          FROM table_name GROUP BY sip_id
        ) b 
    ON table_name.sip_id = b.sip_id
      ) c 
ON table_name.primary_key = c.primary_key 
SET sip_count=c.count

Answer 2

With mysql 8 you can use window function

SELECT 
 `sip_id`, `sip`,
ROW_NUMBER() OVER(PARTITION BY `sip_id`) AS 'sip_count'
FROM sip_count

 CREATE TABLE sip_count ( `sip_id` INTEGER, `sip` INTEGER, `sip_count` INTEGER ); INSERT INTO sip_count (`sip_id`, `sip`, `sip_count`) VALUES ('1', '1', '2'), ('1', '1', '2'), ('2', '1', '3'), ('2', '1', '3'), ('2', '1', '3'), ('4', '1', '2'), ('4', '1', '2'), ('3', '1', '3'), ('3', '1', '3'), ('3', '1', '3');

\n✓ \n\n✓ \n

SELECT `sip_id`, `sip`, ROW_NUMBER() OVER(PARTITION BY `sip_id`) AS 'sip_count' FROM sip_count

\nsip_id |  sip | sip_count \n-----: |  --: |  --------: \n     1 |  1 |  1 \n     1 |  1 |  2 \n     2 |  1 |  1 \n     2 |  1 |  2 \n     2 |  1 |  3 \n     3 |  1 |  1 \n     3 |  1 |  2 \n     3 |  1 |  3 \n     4 |  1 |  1 \n     4 |  1 |  2 \n

db<>fiddle here

Answer 3

I tried the below query and it gave me the result you are looking for.

UPDATE SipDetails 
SET sip_count = (SELECT (MAX(sp2.sip_count) + 1)
                FROM SipDetails sp2 
                WHERE sp2.sip_id = SipDetails.sip_id);

Please note: [SipDetails] should be replaced with your relevant table name.

Below mentioned is the result of running the above query. I initially set the "sip_count" column value to 0 (zero), before the update.