Puede ver esto funcionando en SQL Fiddle:http://sqlfiddle.com/#!3/ 8c3ee/32
Aquí está el meollo:
with parsed as (
select
commasepa,
root.value('(/root/s/col[@name="X"])[1]', 'varchar(20)') as X,
root.value('(/root/s/col[@name="Y"])[1]', 'varchar(20)') as Y,
root.value('(/root/s/col[@name="Z"])[1]', 'varchar(20)') as Z,
root.value('(/root/s/col[@name="A"])[1]', 'varchar(20)') as A,
root.value('(/root/s/col[@name="B"])[1]', 'varchar(20)') as B,
root.value('(/root/s/col[@name="C"])[1]', 'varchar(20)') as C,
root.value('(/root/s/col[@name="D"])[1]', 'varchar(20)') as D
FROM
(
select
commasepa,
CONVERT(xml,'<root><s><col name="' + REPLACE(REPLACE(COMMASEPA, '=', '">'),',','</col></s><s><col name="') + '</col></s></root>') as root
FROM
samp
) xml
)
update
samp
set
samp.x = parsed.x,
samp.y = parsed.y,
samp.z = parsed.z,
samp.a = parsed.a,
samp.b = parsed.b,
samp.c = parsed.c,
samp.d = parsed.d
from
parsed
where
parsed.commasepa = samp.commasepa;
Divulgación completa:soy el autor de sqlfiddle.com
Esto funciona convirtiendo primero cada cadena commasepa en un objeto XML que se ve así:
<root>
<s>
<col name="X">1</col>
</s>
<s>
<col name="Y">2</col>
</s>
....
</root>
Una vez que tengo la cadena en ese formato, uso las opciones de consulta que admite SQL Server 2005 (y versiones posteriores), que es .value('(/root/s/col[@name="X"])[1]', 'varchar(20)') parte. Selecciono cada una de las columnas potenciales individualmente, para que se normalicen y completen cuando estén disponibles. Con ese formato normalizado, defino el conjunto de resultados con una expresión de tabla común (CTE) que llamé 'analizado'. Este CTE luego se vuelve a unir en la declaración de actualización, de modo que los valores se puedan completar en la tabla original.
