alter table AKUZ.T_CDA_STUDY_SAMPLE_INFO rename column sampleid to sampleid_old;

ALTER TABLE AKUZ.T_CDA_STUDY_SAMPLE_INFO ALTER COLUMN "sampleid_old" SET DATA TYPE varchar(255);

ALTER TABLE AKUZ.T_CDA_STUDY_SAMPLE_INFO ALTER COLUMN "sampleid_old" DROP NOT NULL;