SQL - ayuda con consulta select distinct() order by substring

columna1

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1/2

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select distinct(columna1) from tabla order by substring(columna1 from 0  for (position('/' in columna1)))

select distinct SQ.columna1

from   (select columna1

             , substring(columna1 from 0  for (position('/' in columna1))) as orden

        from tabla) SQ

order by SQ.orden

select distinct(columna1) from tabla order by substring(columna1 from 1  for instr(columna1,'/')))

select

  T.columna1

from

(

  select

  distinct (columna1) columna1, substring(columna1 from 0  for (position('/' in columna1))) as orden

  from tabla

  order by substring(columna1 from 0  for (position('/' in columna1)))

) T;