UPDATE c
SET c.CliCarCon1 = 'B'
    FROM TESISSEG.dbo.Clientes c
WHERE c.CliFecCar1 != '1753-01-01'
  AND TRIM(c.CliCarCon1) = ''
  AND EmpID = 2

UPDATE c
SET c.CliCarCon2 = 'B'
    FROM TESISSEG.dbo.Clientes c
WHERE c.CliFecCar2 != '1753-01-01'
  AND TRIM(c.CliCarCon2) = ''
  AND EmpID = 2

UPDATE c
SET c.CliCarCon3 = 'B'
    FROM TESISSEG.dbo.Clientes c
WHERE c.CliFecCar3 != '1753-01-01'
  AND TRIM(c.CliCarCon3) = ''
  AND EmpID = 2

UPDATE c
SET c.CliCarCon4 = 'B'
    FROM TESISSEG.dbo.Clientes c
WHERE c.CliFecCar4 != '1753-01-01'
  AND TRIM(c.CliCarCon4) = ''
  AND EmpID = 2

UPDATE c
SET c.CliCarCon5 = 'B'
    FROM TESISSEG.dbo.Clientes c
WHERE c.CliFecCar5 != '1753-01-01'
  AND TRIM(c.CliCarCon5) = ''
  AND EmpID = 2

UPDATE c
SET c.CliCarCon6 = 'B'
    FROM TESISSEG.dbo.Clientes c
WHERE c.CliFecCar6 != '1753-01-01'
  AND TRIM(c.CliCarCon6) = ''
  AND EmpID = 2