data AS (SELECT CAST('{"f1":["v1","v2"],"f2":"v3"}' AS varchar(max)) AS ResponseJSON),

parser AS

(

SELECT

Level = 1,

OpenClose = 1,

P = p.P,

S = SUBSTRING(d.ResponseJSON, 1, NULLIF(p.P, 0) - 1),

C = SUBSTRING(d.ResponseJSON, NULLIF(p.P, 0), 1),

ResponseJSON = SUBSTRING(d.ResponseJSON, NULLIF(p.P, 0) + 1, 999999)

FROM

data AS d

CROSS APPLY (SELECT PATINDEX('%[[{]%', d.ResponseJSON)) AS p (P)

UNION ALL

SELECT

Level = ISNULL(d.OpenClose - 1, 0) + d.Level + ISNULL(oc.OpenClose, 0),

OpenClose = oc.OpenClose,

P = d.P + ISNULL(p.P, 0),

S = SUBSTRING(d.ResponseJSON, 1, p.P - 1),

C = c.C,

ResponseJSON = SUBSTRING(d.ResponseJSON, p.P + 1, 999999)

FROM

parser AS d

CROSS APPLY (VALUES (NULLIF(PATINDEX('%[[{}:,]%', d.ResponseJSON), 0), NULLIF(PATINDEX('%]%', d.ResponseJSON), 0))) AS p_ (a, b)

CROSS APPLY (VALUES (CASE WHEN p_.a < p_.b OR p_.b IS NULL THEN p_.a ELSE p_.b END)) AS p (P)

CROSS APPLY (SELECT SUBSTRING(d.ResponseJSON, p.P, 1)) AS c (C)

CROSS APPLY (SELECT CASE WHEN c.C IN ('[', '{') THEN 1 WHEN c.C IN (']', '}') THEN 0 END) AS oc (OpenClose)

WHERE 1=1

AND p.P <> 0

)

*

parser