No cursors please! DB2 syntax varies from SQL Server.
Just because it took me an hour to find it....I wish the syntax would be the same...but they're not
UPDATE ASSESS_AUDIT A1
SET FIRST_NAME = (SELECT SUB_FIRST_NAME
FROM ORG_TREE O1
WHERE A1.EMPL_ID = O1.EMPL_ID)
WHERE FIRST_NAME = ' '
AND EXISTS (SELECT * FROM ORG_TREE O2
WHERE A1.EMPL_ID = O2.EMPL_ID);
Another example
UPDATE SS_FAMILY_TREE_MAP SFTM
SET ORG_NAME = ( SELECT SUBSTR(SOR.SS_ORG_NAME,1,25)
FROM SS_ORG_REL SOR
WHERE SFTM.SS_ORG_CD = SOR.SS_ORG_CD
AND SFTM.SS_STRUCTURE_NAME = SOR.STRUCTURE_NAME)
WHERE ORG_NAME IS NULL OR ORG_NAME = ' '
;