Question

I need to limit the row number to one unique row in SQL query. Here’s sample data to recognize what I’m talking about:

john doe 3000 fog horn drive , ky 40444
john doe 3001 merry lane , ky 40484

I want to return the first one in the list here’s my query :

Select 
    DISTINCT p.personID, e.citizenship, 
    rtrim(i.lastname + CASE WHEN i.suffix IS NULL THEN '' ELSE ' ' + i.suffix END) + ', ' + i.firstname + (CASE WHEN i.middlename IS NULL THEN '' ELSE ' ' + i.middlename END) StuName, 
    e.grade, i.gender, p.studentNumber, e.citizenship, e.adult, i.birthdate, 
    e.disability1, e.disability2, ad.city, e.displacedHomemaker, e.homeSchooled, 
    e.localStudentNumber, e.migrant, e.modifiedDate, e.modifiedByID,
    rtrim(Staff.lastname + CASE WHEN Staff.suffix IS NULL THEN '' ELSE ' ' + Staff.suffix END) + ', ' + Staff.firstname + (CASE WHEN Staff.middlename IS NULL THEN '' ELSE ' ' + Staff.middleName END) Staffname, 
    Staff.personID Staffid, i.lastname, i.firstname, i.middlename, i.ssn, 
    ad.phone, ad.state, ad.zip, ad.addressLine1
FROM 
    Person p 
LEFT join 
    Enrollment e ON e.personID = p.personID And isnull(e.noshow, 0) = 0 
LEFT join 
    EnrollmentKY ky ON ky.enrollmentID = e.enrollmentID 
LEFT join 
    [Identity] i ON i.identityID = p.currentIdentityID And i.personID = p.personID 
INNER join 
    Calendar c ON c.calendarID = e.calendarID 
INNER join 
    SchoolYear sy ON sy.endYear = c.endYear AND sy.active = 1 
JOIN 
    staffMember Staff ON Staff.personID = e.modifiedByID 
--join view_students s ON  s.personID = i.personID
left join 
    v_MailingAddress ad ON ad.personID = i.personID And ad.relatedBy = 'household'
                        And ad.endDate IS NULL And isnull(ad.secondary, 0) = 0 
order by 
    i.lastname, i.firstname, i.middlename

edit: need to only pick first row in SQL code because I have a problem with people that have multiple addresses it puts two rows for them and i only need first row of data for the person that has multiple addresses.

Answer 1

If the personId is distinct for each of the records and they just have a different address, then you can add a field for the row_number() and then only select the records where the row_number = 1:

select *
from 
(
  Select p.personID,
    e.citizenship, 
    rtrim(i.lastname + CASE WHEN i.suffix IS NULL THEN '' ELSE ' ' + i.suffix END) + ', ' + i.firstname + (CASE WHEN i.middlename IS NULL THEN '' ELSE ' ' + i.middlename END) StuName, 
    e.grade, 
    i.gender, 
    p.studentNumber, 
    e.citizenship, 
    e.adult, 
    i.birthdate, 
    e.disability1, 
    e.disability2, 
    ad.city, 
    e.displacedHomemaker, 
    e.homeSchooled,
    e.localStudentNumber,
    e.migrant,
    e.modifiedDate,
    e.modifiedByID,
    rtrim(Staff.lastname + CASE WHEN Staff.suffix IS NULL THEN '' ELSE ' ' + Staff.suffix END) + ', ' + Staff.firstname + (CASE WHEN Staff.middlename IS NULL THEN '' ELSE ' ' + Staff.middleName END) Staffname, 
    Staff.personID Staffid,
    i.lastname, 
    i.firstname, 
    i.middlename,
    i.ssn, 
    ad.phone, 
    ad.state, 
    ad.zip, 
    ad.addressLine1,
    row_number() over(partition by p.personid order by p.personid) rn -- add this field
  FROM Person p 
  LEFT join Enrollment e 
    ON e.personID = p.personID 
    And isnull(e.noshow,0)=0 
  LEFT join EnrollmentKY ky 
    ON ky.enrollmentID = e.enrollmentID 
  LEFT join [Identity] i 
    ON i.identityID = p.currentIdentityID 
    And i.personID = p.personID 
  INNER join Calendar c 
    ON c.calendarID = e.calendarID 
  INNER join SchoolYear sy 
    ON sy.endYear = c.endYear 
    AND sy.active = 1 
  JOIN staffMember Staff 
    ON Staff.personID = e.modifiedByID 
  --join view_students s ON  s.personID = i.personID
  left join v_MailingAddress ad 
    ON ad.personID = i.personID 
    And ad.relatedBy = 'household'
    And ad.endDate IS NULL 
    And isnull(ad.secondary,0)=0 
) x
where x.rn = 1
order by x.lastname, x.firstname, x.middlename