[英]MySQL stored procedure iterate through multiple values with no cursor used return Error Code: 1172. Result consisted of more than one row
我创建了此MySQL存储过程来解决本文中有关SO的问题 。
步骤如下:
CREATE DEFINER=`root`@`localhost` PROCEDURE `new_procedure`()
BEGIN
DECLARE n, i INT DEFAULT 0;
DECLARE pid VARCHAR(20);
DROP temporary table if exists tmp;
CREATE temporary table tmp
SELECT
t1.patient_id
FROM
consultation t1
LEFT JOIN diagnosis t2
ON t1.diagnosis_id = t2.diagnosis_id
LEFT JOIN visit t3
ON t3.visit_id = t1.visit_id
LEFT JOIN patient t4
ON t4.patient_id = t3.patient_id
LEFT JOIN diabetes_assessment t5
ON t5.patient_id = t4.patient_id
WHERE
t2.diagnosis_name LIKE '%Diabetes%'
AND t1.clinic_id = '361'
AND t3.visit_status="Active"
GROUP BY t1.patient_id ;
set i=1;
SELECT count(*) INTO n FROM tmp;
SELECT patient_id into pid FROM tmp;
while i<=n DO
set pid = (select patient_id from tmp);
SELECT
t1.patient_id,
CONVERT(aes_decrypt(t4.patient_name_en, 'key') USING utf8mb4) as patient_name_en,
min(t3.date_of_visit) as date_of_visit,
t2.diagnosis_name,
max(ifnull(t5.date_of_assessment, 'N/A')) as date_of_assessment,
ifnull(t5.assessment_result, 0) as assessment_result
FROM consultation t1
LEFT JOIN diagnosis t2
ON t1.diagnosis_id = t2.diagnosis_id
LEFT JOIN visit t3
ON t3.visit_id = t1.visit_id
LEFT JOIN patient t4
ON t4.patient_id = t3.patient_id
LEFT JOIN diabetes_assessment t5
ON t5.patient_id = t4.patient_id
WHERE
t2.diagnosis_name LIKE '%Diabetes%' AND
t1.patient_id = pid AND
t1.clinic_id = '361' AND
t3.visit_status="Active"
GROUP BY
t1.patient_id,
t2.diagnosis_name,
t3.date_of_visit,
t4.patient_name_en,
t5.date_of_assessment,
t5.assessment_result
ORDER BY t5.date_of_assessment DESC LIMIT 1;
set i = i + 1;
END WHILE;
END
我会解释一下。 下面的查询将得到patient_ids
按组patient_id
,这样的问题only full group by
解决:
DROP temporary table if exists tmp;
CREATE temporary table tmp
SELECT t1.patient_id
FROM consultation t1
LEFT JOIN diagnosis t2
ON t1.diagnosis_id = t2.diagnosis_id
LEFT JOIN visit t3
ON t3.visit_id = t1.visit_id
LEFT JOIN patient t4
ON t4.patient_id = t3.patient_id
LEFT JOIN diabetes_assessment t5
ON t5.patient_id = t4.patient_id
WHERE t2.diagnosis_name LIKE '%Diabetes%' AND t1.clinic_id = '361'
AND t3.visit_status="Active"
GROUP BY t1.patient_id ;
然后,我将计算该临时表中的行数:
set i=1;
SELECT count(*) INTO n FROM tmp;
结果是2个患者ID。
因此,我需要遍历每个患者的ID:
select patient_id into pid FROM tmp;
在此查询中:
while i<=n DO
set pid = (select patient_id from tmp);
SELECT
t1.patient_id,
CONVERT(aes_decrypt(t4.patient_name_en, 'key') USING utf8mb4) as patient_name_en,
min(t3.date_of_visit) as date_of_visit,
t2.diagnosis_name,
max(ifnull(t5.date_of_assessment, 'N/A')) as date_of_assessment,
ifnull(t5.assessment_result, 0) as assessment_result
FROM consultation t1
LEFT JOIN diagnosis t2
ON t1.diagnosis_id = t2.diagnosis_id
LEFT JOIN visit t3
ON t3.visit_id = t1.visit_id
LEFT JOIN patient t4
ON t4.patient_id = t3.patient_id
LEFT JOIN diabetes_assessment t5
ON t5.patient_id = t4.patient_id
WHERE
t2.diagnosis_name LIKE '%Diabetes%' AND
t1.patient_id = pid AND
t1.clinic_id = '361' AND
t3.visit_status="Active"
GROUP BY
t1.patient_id,
t2.diagnosis_name,
t3.date_of_visit,
t4.patient_name_en,
t5.date_of_assessment,
t5.assessment_result
ORDER BY t5.date_of_assessment DESC LIMIT 1;
set i = i + 1;
END WHILE;
我认为我的问题出在以下两行:
select patient_id into pid FROM tmp;
和
set pid = (select patient_id from tmp);
错误是:
我不想使用游标,因为我们的教授曾经说过,游标既有资源又是错误的做法。
错误代码:1172。结果由多个行组成
如果要获取两个不同的患者id并要遍历两个ID,则需要使用CURSOR
,例如:
DECLARE patient_id_cursor CURSOR FOR SELECT patient_id FROM tmp;
OPEN patient_id_cursor;
FETCH cursor_name INTO pid;
/*
Logic to process `pid`
*/
CLOSE patient_id_cursor;
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