SELECT m.*,
	coalesce(sb.somecol, sd.somecol, tb.somecol, td.somecol) AS somecol
FROM KPI_Master m
LEFT JOIN SDCCHBLOCKING sb ON m.NE = sb.NE AND m.KPI = 'SDCCHBLOCKING'
LEFT JOIN SDCCHDROP     sd ON m.NE = sd.NE AND m.KPI = 'SDCCHDROP'
LEFT JOIN TCHBLOCKING   tb ON m.NE = tb.NE AND m.KPI = 'TCHBLOCKING'
LEFT JOIN TCHDROP       td ON m.NE = td.NE AND m.KPI = 'TCHDROP'