This worked with the following:

INSERT tbl(userid, clientid, projectid)

SELECT DISTINCT 'ZXY', a.clientid, a.projectid

FROM tbl a

WHERE NOT...

Thanks Eugene,

The table is used as a lookup by the application. So for example:

We have a table called Table.Project

PROJECTID_CLIENTID_PROJECTNAME_STATUS

000001_012345_PROJECTRED_R

000002_012345_PROJECTRED_R

000034_012346_PROJECTBLUE_R

000034_012346_PROJECTBLUE_R

000033_012343_PROJECTFISH_O

For all the projects that are marked with the status 'R'...