Question

I'm currently using an API through Azure to connect to my app. I'm running a query which populates the list view for the user's medications. The user has the choice whether to add a diagnosis along with their medication, or not. If the user adds a medication and diagnosis, the query is successful and will populate the database and list view. But if the user does not add a diagnosis, the database is updated successfully and the userdiagnosis field is blank, but it will not show up on the list view on the app.

Is there any way to allow a null value to run in the query and still pull the data successfully?

This is my current query:

var api = {
// an example of executing a SQL statement directly
get: (request, response, next) => {
    var query = {
        sql: 'SELECT  dbo.usermedication.id, \
        dbo.medicine.id AS medicationid,  \
        dbo.medicine.medname, \
        dbo.usermedication.isactive, \
        dbo.usermedication.reminder, \
        dbo.usermedication.communityfeedback, \
        dbo.usermedication.frequency, \
        dbo.usermedication.directions, \
        dbo.medicine.dosage, \
        dbo.usermedication.datetimetotake,  \
        dbo.userdiagnosis.id as "userdiagnosisid", \
        dbo.diagnosis.id AS diagnosisid, \
        dbo.diagnosis.diagnosistext \
        FROM dbo.usermedication 
        INNER JOIN dbo.medicine ON dbo.usermedication.medicationid = dbo.medicine.id  
        INNER JOIN dbo.userdiagnosis ON dbo.usermedication.userdiagnosisid = dbo.userdiagnosis.id  
        INNER JOIN dbo.diagnosis ON dbo.userdiagnosis.diagnosisid = dbo.diagnosis.id 
        WHERE dbo.usermedication.userid = @userid AND dbo.usermedication.isactive = 1',
        parameters: [
            { name: 'userid', value: request.query.userid }
        ]
    };

    request.azureMobile.data.execute(query)
        .then(function (results) {
            response.json(results);
        });
}

};

module.exports = api;

Answer 1

据您从给定的问题陈述中了解到，如果用户未添加诊断，则dbo.diagnosis表将没有条目，但dbo.usermedication将成功更新。由于您在这些表上使用了INNER JOIN，因此显然列表将没有，因为dbo.diagnosis表中没有匹配的记录。

如果您考虑在dbo.diagnosis上使用LEFT JOIN，那么即使诊断表中的值为空，您也可以从userMedication表中获取记录。

如果这是期望的，请尝试。

也许您可以尝试运行以下内容

WITH  (SELECT * FROM dbo.userdiagnosis  
    INNER JOIN dbo.diagnosis ON dbo.userdiagnosis.diagnosisid = dbo.diagnosis.id ) AS diagnosisDetails,
SELECT  dbo.usermedication.id, \
    dbo.medicine.id AS medicationid,  \
    dbo.medicine.medname, \
    dbo.usermedication.isactive, \
    dbo.usermedication.reminder, \
    dbo.usermedication.communityfeedback, \
    dbo.usermedication.frequency, \
    dbo.usermedication.directions, \
    dbo.medicine.dosage, \
    dbo.usermedication.datetimetotake,  \
    DiagnosisDetails.id as "userdiagnosisid", \
    DiagnosisDetails.diagnosistext \
    FROM dbo.usermedication 
    INNER JOIN dbo.medicine ON dbo.usermedication.medicationid = 
dbo.medicine.id  
    LEFT JOIN diagnosisDetails ON dbo.usermedication.userdiagnosisid = diagnosisDetails.id  
    WHERE dbo.usermedication.userid = @userid AND dbo.usermedication.isactive = 1;

SQL Query - pulling a query with a null value

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