Table DDL is:

CREATE TABLE INVOICES
(
INVOICE_NO INTEGER NOT NULL,
DATE_DEL DATE,
ACC_NUM INTEGER NOT NULL,
ROUTE CHAR( 5) CHARACTER SET NONE COLLATE
NONE,
REF_NO CHAR( 5) CHARACTER SET NONE COLLATE
NONE,
SUB_TOTAL NUMERIC( 4, 2),
TAX_SALES NUMERIC( 4, 2),
TAX_COUNTY NUMERIC( 4, 2),
DRUMS_DEL SMALLINT,
DRUMS_RET SMALLINT,
DRUM_DEP NUMERIC( 4, 2),
R_F_CHRG NUMERIC( 4, 2),
REC_BY CHAR( 20) CHARACTER SET NONE COLLATE
NONE,
DEL_BY CHAR( 20) CHARACTER SET NONE COLLATE
NONE,
PAID NUMERIC( 4, 2),
CHECK_NO CHAR( 5) CHARACTER SET NONE COLLATE
NONE,
CHRG_ACC NUMERIC( 4, 2),
REMARKS CHAR( 5) CHARACTER SET NONE COLLATE
NONE,
AMT_PD_INV NUMERIC( 4, 2),
AMT_PD_ACC NUMERIC( 4, 2),
PO_NUM CHAR( 15) CHARACTER SET NONE COLLATE
NONE,
TERR CHAR( 2) CHARACTER SET NONE COLLATE
NONE,
SP_TAX NUMERIC( 4, 2),
POSTED CHAR( 1) CHARACTER SET NONE COLLATE
NONE,
APPLIED CHAR( 1) CHARACTER SET NONE COLLATE
NONE,
TOTAL NUMERIC( 2, 2) NOT NULL
)

I want the INVOICE_NO column to be the primary key

Jim