svk svk - 7 months ago 16
SQL Question

use the If else condition for selecting the column in mysql?

I am having two tables like this.Both are separate tables

AccountNo User Name
----------------------------------
1 U a
2 U b
3 U c


And another table contains the following structure

TempAccountNo Mycolumn AccountNo
------------------------------------------
4 X 2341
5 Y 2
6 Z 2568


I need to select the AccountNo or TempAccountNo,Mycolumn From table II and the condition is

If (tableII.AccountNo not in table I)


I need to choose
TempAccountNo from table II


else


I need to choose
AccountNo from table II


How can I achieve this.

Answer
   SELECT IF(t1.AccountNo IS NULL, t2.TempAccountNo, t2.AccountNo) AS optional_field
     FROM table2 t2
LEFT JOIN t1 ON t1.AccountNo = t2.AccountNo
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