SQL: Have two two columns of old and new SKUS. Need to pull into a single column with new skus if an-CodePudding

I have two columns with data from Table1 that have the SKU number and New SKU Number. My goal is to query this data as a single column as shown in the 'Desired' Table

 ------- --------      --------- 
| SKU   | NEW_SKU|    | Desired |
 ------- --------     |--------- 
| null  | 1      |    | 1       |
| null  | 1      |    | 1       |
|  2    | null   |    | 2       |
|  2    | 3      |    | 3       |
|  2    | 5      |    | 5       |
 ------- --------      ---------

Currently I have:

SELECT 

SKU
CASE WHEN (SKU IS NOT NULL AND NEW_SKU IS NOT NULL) THEN new_sku
WHEN (SKU IS NULL AND NEW_SKU IS NOT NULL) THEN new_sku
ELSE SKU END AS Product_number

FROM Table1

CodePudding user response：

Use COALESCE here:

SELECT SKU, NEW_SKU, COALESCE(NEW_SKU, SKU) AS Product_number
FROM Table1;

The COALESCE function, as used above, would use the NEW_SKU value if it be non NULL, otherwise would fall back to using the SKU value.