Question

I have a table tbl_a, with “ID” as a primary key, with columnns “GROUP_ID”,”DATE”,”LENGTH”,”VALID”,”CID”

I’d like to make an update query that would update as:

UPDATE all GROUP_ID of 7 to be CID=9, and
if(DATE+LENGTH<TODAY) // I want to say if the DATE column with the addition of LENGTH months is smaller than today’s date(NOW()),

THEN
 SET VALID to be FALSE
for that row.

using YYYY-mm-dd format

so that if the table was

ID| GROUP_ID | DATE       | LENGTH| VALID| CID  
---------------------------------------------------
 1|     7    | 2011-12-01 |     1 |    1 |   2 
 2|     7    | 2012-01-01 |     1 |    1 |   7 
 3|     7    | 2012-02-01 |     1 |    1 |   2 
 4|     7    | 2012-03-01 |     2 |    1 |   3 

after the update:

ID| GROUP_ID | DATE       | LENGTH| VALID| CID  
---------------------------------------------------
 1|     7    | 2011-12-01 |     1 |    0 |   9 // res:2012-12-01,update VALID
 2|     7    | 2012-01-01 |     1 |    0 |   9 // res:2012-02-01,update VALID
 3|     7    | 2012-02-01 |     1 |    1 |   9 // res:2012-03-01,no update for VALID
 4|     7    | 2012-03-01 |     2 |    1 |   9 // res:2012-05-01,no update for VALID

Could you please tell me the syntax for that query?

Answer 1

UPDATE TableX
SET cid = 9
  , valid = CASE WHEN `date` + INTERVAL length MONTH < CURDATE()
                 THEN 0
                 ELSE valid
            END
WHERE group_id = 7