How to appending string into one variable using loop

 hi,

I want to create below dynamic SQL query.  

SELECT A.CUSTOMER_ID, B.MANUFACTURER_ID, B.MANUFACTURER_COUNT FROM CUSTOMER_INFO A , C77VAMn.v_od_manufacturer_count B WHERE A.EC_SERVER_SECURITY_CODE = '77VAMn' UNION 

SELECT A.CUSTOMER_ID, B.MANUFACTURER_ID, B.MANUFACTURER_COUNT FROM CUSTOMER_INFO A , CrLEuVr.v_od_manufacturer_count B WHERE A.EC_SERVER_SECURITY_CODE = 'rLEuVr';

for that I wrote one procedure as below. becuase some value in the above sql are dynamic like schema name and A.EC_SERVER_SECURITY_CODE. but i am facing problem in appending a string, the below procedure return only. . "SELECT A.CUSTOMER_ID, B.MANUFACTURER_ID, B.MANUFACTURER_COUNT FROM CUSTOMER_INFO A , CrLEuVr.v_od_manufacturer_count B WHERE A.EC_SERVER_SECURITY_CODE = 'rLEuVr' UNION"