SQL子查询表达式

Question

SELECT  
    list_diagnosis_seq, list_diagnosis_icd10, 
    list_diagnosis_disease, list_diagnosis_diagtype
FROM    
    cmu_list_diagnosis, cmu_treatment
WHERE   
    (cmu_list_diagnosis.list_diagnosis_date = (SELECT MAX(list_diagnosis_date)  
                                               FROM cmu_list_diagnosis))
    AND cmu_list_diagnosis.treatment_id = (SELECT cmu_list_diagnosis.treatment_id
                                           FROM cmu_list_diagnosis, cmu_treatment 
                                           WHERE cmu_treatment.treatment_date = current_date
                                             AND cmu_treatment.patient_id = (SELECT cmu_patient.patient_id
                                                                             FROM cmu_patient, cmu_treatment
                                                                             WHERE cmu_patient.patient_id = cmu_treatment.patient_id));

I think it's wrong

How to make this code is correct?

thank everyone :)

Answer 1

AND cmu_list_diagnosis.treatment_id = ( SELECT cmu_list_diagnosis.treatment_id FROM cmu_list_diagnosis, cmu_treatment WHERE cmu_treatment.treatment_date = current_date AND cmu_treatment.patient_id = ( SELECT cmu_patient.patient_id

In both the Select references above, either use Top 1 or use IN (Select... instead " = Select"

Answer 2

Without knowing your specific error, or your DBMS, perhaps this translation can help:

SELECT ListDiagnosis.list_diagnosis_seq
    ,ListDiagnosis.list_diagnosis_icd10
    ,ListDiagnosis.list_diagnosis_disease
    ,ListDiagnosis.list_diagnosis_diagtype
FROM cmu_list_diagnosis AS ListDiagnosis
INNER JOIN cmu_treatment AS Treatment ON Treatment.treatment_id = ListDiagnosis.treatment_id
    AND Treatment.treatment_date = CURRENT_DATE
INNER JOIN cmu_patient AS Patient ON Patient.patient_id = Treatment.patient_id
WHERE ListDiagnosis.list_diagnosis_date = (
    SELECT MAX(list_diagnosis_date) AS MaxDate
    FROM cmu_list_diagnosis
);

This converts your syntax to the ANSI syntax, eliminating the double-nesting of subqueries. The INNER JOINs should provide the filtering you are looking for, and the aliasing of the date in the WHERE clause subquery should eliminate errors that certain DBs (such as Teradata) will throw.