Schema error from postgresql update statement - postgresql

Question

I have a POSTGRESQL update statement that I'm trying to rewrite with explicit joins and needing some help whereby the NESTED select statement alias is recognized to execute the outer UPDATE statement. Not sure why the "se" alias for the nested select is NOT recognized. I know I must be missing something basic.
Any help/direction would be appreciated. Thanks.
Error I'm getting:
ERROR: schema "se" does not exist
********** Error **********
ERROR: schema "se" does not exist
SQL state: 3F000
Here is my code:
UPDATE students
SET custom_400011449 = CAST(cfso1.label as integer)+1,
custom_400011770 = 761 --'2016-2017'
FROM (
SELECT se2.student_id, cfso1.id, cfso1.label
FROM students s
INNER JOIN student_enrollment se2
ON s.student_id = se2.student_id
INNER JOIN school_gradelevels sg
ON se2.grade_id = sg.id
INNER JOIN custom_field_log_entries sle
ON se2.student_id = sle.source_id
LEFT JOIN custom_field_select_options cfso1
ON s.custom_400011449 = cfso1.id
LEFT JOIN custom_field_select_options cfso2
ON s.custom_400011770 = cfso2.id
LEFT JOIN custom_field_select_options cfso3
ON sle.log_field4::INT = cfso3.id
WHERE se2.syear =2016
AND s.custom_400011449 IS NOT NULL
AND s.custom_400011898 IS NULL
AND s.custom_400011899 IS NULL
AND sle.field_id = 15 --400010549
AND sle.log_field2 IS NULL
AND cfso2.label = '2015-2016'
AND cfso3.label IN ('LE', 'NL-F', 'NL-S')
AND sg.short_name BETWEEN '01' AND '12'
AND (
SELECT COUNT(school_date)
FROM student_enrollment se
INNER JOIN attendance_calendar ac
ON se.calendar_id = ac.calendar_id
WHERE se.student_id = se2.student_id
AND se.syear =2016 --{SYEAR}
AND ac.syear =2016 --{SYEAR}
AND ac.school_date >= se.start_date
AND ac.school_date <= NOW()
AND (se.end_date IS NULL OR ac.school_date <= se.end_date)
AND se.custom_9 IS NULL
AND se2.start_date >= '2016-08-22'
GROUP BY se.student_id
HAVING COUNT(ac.school_date) >= 59)
>= 59) AS se
LEFT JOIN custom_field_select_options cfso1
ON se.cfso1.id = cfso1.id
WHERE students.student_id = se.student_id

Answer 1

I found my problem whereby I had a syntax error in the ON condition "se.cfso1.id". Once I cleared that up the problem was resolved.