To realize a service, determining a clob field, if clob is empty, the process returns', clob if not empty, is used xmltype (xmlname) .extract ( '// tumorRecord / recordTimestamp / text ()'). Getstringval ( ) resolved clob
解决办法：CASE WHEN ti.DOS_CONT IS NULL THEN '' ELSE xmltype(xmlname).extract('//tumorRecord/effect/text()').getstringval() END
When doing simple judgment, this can be used as the use of java switch case, doing complex judgment, use of usage when xxx then xxx