Question

I am trying to join to tables as image attached shows,

table 1 will have exactly the same records as table 2 except one field with is not equal

I would like to merge them so i will have the extended table :

1. have all records from table2, if we ignore isempty field, table 1 is always in table2

2. when table1.isEmpty=1 , the merged result will have isempty=1, and that record will be overwritten

check attached images for more details

the table 3 as shown, will have all the records from table 2 but overwritten when necessary

Answer 1

SELECT A.ID, A.NAME, A.DESC, CASE B.ISEMPTY
                WHEN 1 THEN 1
                ELSE A.ISEMPTY
                END CASE AS ISEMPTY 
FROM TABLE2 A
LEFT JOIN TABLE1 B ON A.ID=B.ID