merge 2 column into 1

Shambhu Rai 1,406 Reputation points

Hi Expert, create table table11( col1 char,col2 int,col3 int)

insert into table11 values(1, 2,3) insert into table11 values(2, 4,6) insert into table11 values(3, 6,9) insert into table11 values(4, 8,12) 

----case condition----------------------------------------------------

case when col1=2 then col2 =0 
case when col1=3 then col2 =0 
case when col1=1 then col3 =0 
case when col1=4 then col3 =0

expected output: col1 and col2 should be merged via removing the 0 values User's image

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Accepted answer
  1. Alistair Ross 7,101 Reputation points Microsoft Employee

    Hello If I understand, you are trying to create a table and insert values into it using SQL. However, the CASE statements you provided are not valid SQL syntax. To update the values in the table based on certain conditions, you can use an UPDATE statement with a CASE expression. Here’s an example that should achieve the desired result:

    CREATE TABLE table11 (
        col1 CHAR,
        col2 INT,
        col3 INT
    INSERT INTO table11 VALUES (1, 2, 3);
    INSERT INTO table11 VALUES (2, 4, 6);
    INSERT INTO table11 VALUES (3, 6, 9);
    INSERT INTO table11 VALUES (4, 8, 12);
    UPDATE table11
    SET col2 = CASE
        WHEN col1 = 2 THEN 0
        WHEN col1 = 3 THEN 0
        ELSE col2
    col3 = CASE
        WHEN col1 = 1 THEN 0
        WHEN col1 = 4 THEN 0
        ELSE col3

    I hope this helps Alistair

3 additional answers

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  1. Viorel 113K Reputation points

    If there are no other "0", then try this:

    	col2 = coalesce(case when col1 not in (2, 3) then col2 end, case when col1 not in (1, 4) then col3 end) 
    from table11
    order by col1
    0 comments No comments

  2. Shambhu Rai 1,406 Reputation points

    How to merge this 2 column post changes

    0 comments No comments

  3. CosmogHong-MSFT 23,796 Reputation points Microsoft Vendor

    Hi @Shambhu Rai

    Try this query:

    select col1
          ,case when col1=2 or col1=3 then col3  
    	        when col1=1 or col1=4 then col2 end as col2
    from table11

    Best regards,

    Cosmog Hong

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