Sqlサブクエリの内部結合

Question

サブクエリを使用してこのクエリを実行しようとしていますが、正しい結果を得るために、ここで結果を取得できません。

SELECT u.uv_id ID 
    , d.sd_code Code 
    , u.uv_name Title 
    , u.uv_nirf Nirf 
    , (SELECT sd_code 
      FROM vm_university_type t 
      JOIN vm_seo_detail d 
      ON t.ut_id = d.sd_ty_id 
      AND d.sd_ty = 'vm_university_type') AS 'University Type' 
    , a.ab_name 'Approved By' 
    , u.uv_seats Seats 
    , g.ug_name 'University Group' 
    FROM vm_universities u 
    JOIN vm_seo_detail d 
    ON u.uv_id = d.sd_ty_id 
    AND d.sd_ty = 'vm_universities' 
    JOIN vm_university_type t 
    ON u.uv_ut_id = t.ut_id 
    JOIN vm_approved_by a 
    ON u.uv_ab_id = a.ab_id 
    JOIN vm_caste c 
    ON u.uv_c_id = c.caste_id 
    JOIN vm_university_groups g 
    ON u.uv_ug_ids = g.ug_id; 

私はあなたがメインクエリにバインドされますサブクエリのWHERE節を、忘れてしまったようにこのエラーSubquery returns more than 1 row

Answer 1

(SELECT `sd_code` FROM vm_university_type INNER JOIN vm_seo_detail ON (vm_university_type.ut_id = vm_seo_detail.sd_ty_id AND vm_seo_detail.sd_ty = 'vm_university_type') WHERE vm_university_type.ut_id=vm_universities.uv_ut_id) AS 'University Type' , 

Answer 2

SELECT `sd_code` FROM vm_university_type INNER JOIN vm_seo_detail ON (vm_university_type.ut_id = vm_seo_detail.sd_ty_id AND vm_seo_detail.sd_ty = 'vm_university_type') 

が見えました。何かのように

WHERE vm_university_type.ut_id=vm_universities.uv_ut_id 

psです。メインクエリのvm_university_typeにすでに参加している場合、なぜこのサブクエリが必要なのですか？

Answer 3

サブクエリはまったく必要ありません。列CodeのSELECTには、University Type

が含まれています。

SELECT vm_universities.uv_id AS 'ID' , vm_seo_detail.sd_code AS 'Code', 
vm_universities.uv_name AS 'Title' , vm_universities.uv_nirf AS 'Nirf', 
vm_approved_by.ab_name AS 'Approved By' , vm_universities.uv_seats as 'Seats', 
vm_university_groups.ug_name AS 'University Group' 
FROM vm_universities INNER JOIN vm_seo_detail 
ON (vm_universities.uv_id = vm_seo_detail.sd_ty_id 
     AND vm_seo_detail.sd_ty = 'vm_universities') 
INNER JOIN vm_university_type 
ON (vm_universities.uv_ut_id = vm_university_type.ut_id) 
INNER JOIN vm_approved_by 
ON (vm_universities.uv_ab_id = vm_approved_by.ab_id) 
INNER JOIN vm_caste 
ON (vm_universities.uv_c_id = vm_caste.caste_id) 
INNER JOIN vm_university_groups 
ON (vm_universities.uv_ug_ids = vm_university_groups.ug_id);