Find operations required to get result

TSQL(sqlserver 2016) 310 294 280 bytes

What a wonderful opportunity to write ugly code:

Golfed:

DECLARE @ varchar(max)= '5,5,5'
DECLARE @a varchar(20) = '125'

,@ varchar(max)='';WITH D as(SELECT @a a UNION ALL SELECT STUFF(a,charindex(',',a),1,value)FROM STRING_SPLIT('*,+,./,-,',',')x,d WHERE a like'%,%')SELECT @+=a+','''+REPLACE(a,'.','')+'''),('FROM D WHERE a not like'%,%'EXEC('SELECT y FROM(values('+@+'null,null))g(x,y)WHERE x='+@b)

Try it online

Readable:(insertion of decimal point(.) and removal of the same is necessary in order for sql to accept that 4/5 is not 0 - well removal is for the people testing it)

DECLARE @a varchar(max)= '5,5,5'
DECLARE @b varchar(20) = '5'

,@ varchar(max)=''
;WITH D as
(
  SELECT @a a
  UNION ALL
  SELECT STUFF(a,charindex(',',a),1,value)
  FROM STRING_SPLIT('*,+,./,-,',',')x,d
  WHERE a like'%,%'
)
SELECT @+=a+','''+REPLACE(a,',','')+'''),('
FROM D
WHERE a not like'%,%'

EXEC('SELECT y FROM(values('+@+'null,null))g(x,y)WHERE x='+@b)

This solution can also handle these types of input:

Input :[1,2,3,4,5] 0 Output : 12-3-4-5

Oracle SQL 11.2, 322 304 270 bytes

SELECT o FROM(SELECT REPLACE(SUBSTR(:1,1,1)||REPLACE(SYS_CONNECT_BY_PATH(a||SUBSTR(:1,LEVEL*2+1,1),','),','),'_')o,LEVEL l FROM(SELECT SUBSTR('+-*/_',LEVEL,1)a FROM DUAL CONNECT BY LEVEL<6)CONNECT BY LEVEL<LENGTH(:1)/2)WHERE:2=dbms_aw.eval_number(o)AND l>LENGTH(:1)/2-1;

:1 is the list of digits
:2 is the result searched

Un-golfed :

SELECT o
FROM   (
         SELECT REPLACE(SUBSTR(:1,1,1)||REPLACE(SYS_CONNECT_BY_PATH(a||SUBSTR(:1,LEVEL*2+1,1),','),','),'_')o,LEVEL l 
         FROM ( -- Create one row per operator 
                SELECT SUBSTR('+-*/_',LEVEL,1)a FROM DUAL CONNECT BY LEVEL<6
              ) CONNECT BY LEVEL<LENGTH(:1)/2  -- Create every combination of operators, one per ','
)
WHERE :2=dbms_aw.eval_number(o)  -- filter on result = evaluation
  AND l>LENGTH(:1)/2-1           -- keep only expressions using every digits

Pyth, 23 bytes

Due to security reasons, * and / won't evaluate online, but they theoretically work.

fqeQvTms.ihQd^"+-*/"lth

Test suite with only + and -.