SQL Queries Specialist

I am urgently in need of a SQL expert proficient in MySQL. I require assistance with writing data definition queries.

Work Expectations:

- Writing proficient data definition SQL queries.

- Extensive knowledge of MySQL.

Below is my query. Need to modify the query and get the count as 0 for the column srce_syst_paty_i

SELECT COUNT(*)
FROM (
SELECT
CASE
WHEN PATY_IDNN_BK LIKE '%SAP%' THEN SUBSTR(PATY_IDNN_BK, INSTR(PATY_IDNN_BK, '+') + 1)
WHEN PATY_IDNN_BK LIKE '%BCB%' THEN SUBSTRING_INDEX(PATY_IDNN_BK, '~', -1)
END AS srce_syst_paty_i,
*
FROM dev_enr.cpln_svrq_paty_detl
WHERE day = '02' AND month = '06' AND year = 2023
) src
INNER JOIN (
SELECT *
FROM dev_oal.bv_fcf_svrq_cpln_paty
WHERE day = 02 AND month = 06 AND year = 2023
) trgt ON src.cpln_svrq_idnn_bk = trgt.svrq_idnn_bk
AND src.snap_d = trgt.snap_d
AND src.paty_idnn_bk = trgt.paty_idnn_bk
AND src.paty_seqn_n = trgt.recd_chng_idnn_seqn_n
Where nvl(src.srce_syst_paty_i, ' ') <> nvl(trgt.srce_syst_paty_i, ' ')