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Oracle sql left join problem

Getting error at line 35

see attachment for entire code but

here are the lines in question

LEFT JOIN (select DISTINCT(PERSON_ID, SCHOOL_YEAR, SCHOOL_CODE) from FS_SE_STUDENT_SCHOOL_IEP) SCHOOLIEP
ON SCHOOLIEP.PERSON_ID = STUDENT_REGISTRATIONS.PERSON_ID
AND SCHOOLIEP.SCHOOL_YEAR = STUDENT_REGISTRATIONS.SCHOOL_YEAR
AND SCHOOLIEP.SCHOOL_CODE = STUDENT_REGISTRATIONS.SCHOOL_CODE

Steve Wales

No attachment here ... and no specific error message. Please provide both?

ASKER CERTIFIED SOLUTION

chaau

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Geert G

get rid of the duplicates and then leave the distinct out

LEFT JOIN FS_SE_STUDENT_SCHOOL_IEP SCHOOLIEP
ON SCHOOLIEP.PERSON_ID = STUDENT_REGISTRATIONS.PERSON_ID
AND SCHOOLIEP.SCHOOL_YEAR = STUDENT_REGISTRATIONS.SCHOOL_YEAR
AND SCHOOLIEP.SCHOOL_CODE = STUDENT_REGISTRATIONS.SCHOOL_CODE

Mark Geerlings

Be very careful with the word "distinct" in Oracle queries. Yes, that keyword is supported in Oracle. But it can cause two problems:
1. Oracle's definition of what "distinct" means may be different from what most humans expect, especially if there is a date column involved, and the date values include a non-midnight time-of-day.
2. This forces a sort operation, so depending on how many duplicate rows exists, this can add a significant performance penalty.