mysql - サブクエリで違いの結果を見つけると、mysql エラーで複数の行が返される

Question

次のフィールドを持つ tbl_populations という名前のテーブルがあります。

pk_populationid,residence,value,aspect,gender,fk_tbl_states_stateid

2つの側面の行の差を計算しようとしています

例えば

SELECT fk_tbl_states_stateid, value - (
SELECT value
FROM tbl_populations
WHERE fk_tbl_states_stateid = '16'
AND fk_tbl_districts_districtid = '0'
AND residence = '0'
AND gender = '0'
AND aspect = '2' ) AS difference
FROM tbl_populations
WHERE fk_tbl_states_stateid = '16'
AND fk_tbl_districts_districtid = '0'
AND residence = '0'
AND gender = '0'
AND aspect = '1'

1行を返すので正常に動作しています

すべての性別値を取得したいという複数のデータを取得するために、条件から性別を削除しました。

SELECT fk_tbl_states_stateid,gender, value - (
SELECT value
FROM tbl_populations
WHERE fk_tbl_states_stateid = '16'
AND fk_tbl_districts_districtid = '0'
AND residence = '0'
AND aspect = '2' ) AS difference
FROM tbl_populations
WHERE fk_tbl_states_stateid = '16'
AND fk_tbl_districts_districtid = '0'
AND residence = '0'
AND aspect = '1'  

エラーが発生してSubquery returns more than 1 rowいます。

すべての結果を取得するにはどうすればよいですか?

Answer 1

SELECT Table11.fk_tbl_states_stateid,Table1.Gender,Table1.value - table2.Value as Diff
From
(SELECT *
FROM tbl_populations
WHERE fk_tbl_states_stateid = '16'
AND fk_tbl_districts_districtid = '0'
AND residence = '0'
AND aspect = '2' ) Table1,
(SELECT value,Gender
FROM tbl_populations
WHERE fk_tbl_states_stateid = '16'
AND fk_tbl_districts_districtid = '0'
AND residence = '0'
AND aspect = '1' ) Table2
Where Table1.Gender = Table2.Gender

Answer 2

関数を使用すると、そのように簡単になるはずです