Error in Nested Case statement in MYSQL Query

There is some error in the below nested case statement I am using. Whenever I try to exceute this it's giving these errors:-

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHEN (ISNUMERIC(FORMULA_RESULT) = 1 AND LTRIM(UPPER(MAX_SPEC)) = 'PASS' AND LTRI' at line 461064

Fatal error: Call to a member function num_rows() on a non-object in C:Inetpubwwwdevssvacisystemappslabmodelsm_tests.php on line 396

Code:-

$result = $this->db->query(
            "SELECT * FROM (SELECT `lt`.*, ltm.METHOD_NAME, `lt`.`DATE_INSERTED` AS TEST_DATE, `lt`.`PRODUCT_ID` AS ACTUAL_PRODUCT_ID, `lc`.*, `lp`.`PRODUCT_MAS_ID` AS PRODUCT_NAME, `lp`.`PRODUCT_DESCRIPTION`, `ll`.*, `ld`.DEPARTMENT, `ltl`.`TEST`, ltl.CALCULATOR, `lmu`.`MEASUREMENT`,

            CASE (@result:=TRIM(UPPER(FORMULA_RESULT)))
            WHEN 'PASS'
               THEN IF(QA_MIN_SPEC = FORMULA_RESULT AND QA_MAX_SPEC = FORMULA_RESULT,NULL,'WILL BE OOS')
            WHEN 'FAIL'
               THEN IF(QA_MIN_SPEC = FORMULA_RESULT AND QA_MAX_SPEC = FORMULA_RESULT,NULL,'WILL BE OOS')
            WHEN 'ABSENT'
               THEN NULL
            WHEN 'PRESENT'
               THEN 'WILL BE OOS'
            WHEN 'TNTC'
               THEN 'WILL BE OOS'
             /*CHG0032114 -INC0051173 ->Alphabetic validation added for OOS Cases */  
            WHEN LTRIM(UPPER(FORMULA_RESULT)) LIKE '[a-Z][a-Z]%' AND LTRIM(UPPER(FORMULA_RESULT)) Not IN('PASS','ABSENT','ND') 
                THEN 'WILL BE OOS' 
            /*CHG0032114 -INC0051173 ->Alphabetic validation added for OOS Cases */             
            WHEN 'ND'
               THEN IF(0 >= QA_MIN_SPEC AND 0 <= QA_MAX_SPEC, NULL, 'WILL BE OOS')
            ELSE
                CASE WHEN @result LIKE '<%'
                     THEN
                     IF((REPLACE(FORMULA_RESULT,'<','') - 1) BETWEEN CAST(QA_MIN_SPEC AS DECIMAL(30,15)) AND CAST(QA_MAX_SPEC AS DECIMAL),NULL,'WILL BE OOS')
                    ELSE
                    CASE 
                        WHEN (Category_ID=2) THEN
                        CASE WHEN (CAST(formula_result AS DECIMAL(30,15)) NOT BETWEEN CAST(QA_MIN_SPEC AS DECIMAL(30,15)) AND CAST(QA_MAX_SPEC AS DECIMAL(30,15)))
                          THEN 'WILL BE OOS' 
                    ELSE
                        CASE WHEN (CAST(formula_result AS DECIMAL(30,15)) NOT BETWEEN CAST(ALERT_LIMIT_MIN AS DECIMAL(30,15)) AND CAST(ALERT_LIMIT_MAX AS DECIMAL(30,15))) 
                           THEN 'WILL BE OOA'
                        END                             
                        END


                ELSE
                        CASE WHEN (CAST(formula_result AS DECIMAL(30,15)) NOT BETWEEN CAST(MIN_SPEC AS DECIMAL(30,15)) AND CAST(MAX_SPEC AS DECIMAL(30,15))) 
                        THEN 'WILL BE OOS' 
                    ELSE
                        CASE WHEN (CAST(formula_result AS DECIMAL(30,15)) NOT BETWEEN CAST(ALERT_LIMIT_MIN AS DECIMAL(30,15)) AND CAST(ALERT_LIMIT_MAX AS DECIMAL(30,15)))
                        THEN 'WILL BE OOA'
                       END                             
                       END
                    END

                        WHEN (ISNUMERIC(FORMULA_RESULT) = 1 AND LTRIM(UPPER(MAX_SPEC)) = 'PASS' AND LTRIM(UPPER(MIN_SPEC)) = 'PASS')
                            THEN 'WILL BE OOS'
                        WHEN ISNUMERIC(FORMULA_RESULT) = 1 and LTRIM(UPPER(MAX_SPEC)) = 'ABSENT' and LTRIM(UPPER(MIN_SPEC)) = 'ABSENT'
                            THEN 'WILL BE OOS'
                        WHEN SUBSTRING(FORMULA_RESULT,1,1) = '<' and ISNUMERIC(SUBSTRING(FORMULA_RESULT,2,3)) = 1 and LTRIM(UPPER(MAX_SPEC)) = 'PASS'   and LTRIM(UPPER(MIN_SPEC)) = 'PASS' 
                            THEN 'WILL BE OOS'
                        WHEN SUBSTRING(FORMULA_RESULT,1,1) = '<' and ISNUMERIC(SUBSTRING(FORMULA_RESULT,2,3)) = 1 and LTRIM(UPPER(MAX_SPEC)) = 'ABSENT' and LTRIM(UPPER(MIN_SPEC)) = 'ABSENT'
                            THEN 'WILL BE OOS'  
                END

            END AS will_be_oos,

 $where".$order.") q".$whereFilters



        );