Nested Cursors in MYSQL, cursor not working as expected - mysql

Question

I have created an SP in MYSQL to get values by date, by the sensor. My SP executes the inner cursor correctly but the outer cursor(1st cursor) is not executed. i.e. I only get 1 day of data, dateTable has a week's data.
CREATE PROCEDURE `Analysis`()
BEGIN
declare v_date datetime;
declare v_sensor varchar(50);
DECLARE datecursHandler,sensorCursHandler BOOLEAN DEFAULT FALSE;
Block1: BEGIN
declare datecursor CURSOR for
select distinct date from dateTable;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET datecursHandler = TRUE;
Open datecursor;
datecurs: loop
FETCH datecursor into date;
IF datecursHandler THEN
CLOSE datecursor;
LEAVE datecurs;
END IF;
Block2: BEGIN
declare sensorCursor CURSOR for
select distinct sensor from sensorTable ;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET sensorcur = TRUE;
Open sensorCursor;
senscurs: loop
FETCH sensorCursor into sensor;
IF sensorcur THEN
SET sensorcur = False;
CLOSE sensorCursor;
LEAVE senscurs;
END IF;
Insert into temptable(
sensorValue,
DateID,
TimeID,
TotalCount,
TotalDistinctCount
)
SELECT
sensor AS sensorValue,
DATE_FORMAT(firstdate, '%Y%m%d') AS DateID,
HOUR(firstdate) + 1 AS TimeID,
COUNT(*) AS totalcount,
COUNT(DISTINCT sensor) AS sensordistinctcount
FROM
(SELECT
sensor AS sensor,
first_seen AS DeviceFirstSeen,
last_seen AS DeviceLastSeen,
DATE_FORMAT(FROM_UNIXTIME(first_seen), '%Y/%m/%d %k:%i:%s.%f') AS firstdate,
DATE_FORMAT(FROM_UNIXTIME(last_seen), '%Y/%m/%d %k:%i:%s.%f') AS lastdate,
FROM
sensorTable
INNER JOIN sensorTable2 ON sensorTable.ID = sensorTable2.ID
WHERE sensorTable.DeviceFirstSeen BETWEEN date_format(date_sub(date,interval 1 day),'%Y-%m-%d 15:00:00') AND date_format(date,'%Y-%m-%d 14:59:59')) a
GROUP BY DATE_FORMAT(firstdate, '%Y%m%d') , HOUR(firstdate) + 1;
end loop Maccurs;
END Block2;
END loop datecurs;
END Block1;
END
Can anyone please help me debug my code? I have researched but so far my code looks correct as per my research but doesn't work as expected.
Required Output:
Get counts of all the sensors for each day each hour that is selected from dateTable.

Answer 1

Try the below procedure, Since the issue might be incorrect closing of cursor.
CREATE PROCEDURE `Analysis`()
BEGIN
declare v_date datetime;
declare v_sensor varchar(50);
DECLARE datecursHandler,sensorCursHandler BOOLEAN DEFAULT FALSE;
Block1: BEGIN
declare datecursor CURSOR for
select distinct date from dateTable;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET datecursHandler = TRUE;
select distinct date from dateTable; #what is the result set you are getting?
Open datecursor;
datecurs: loop
FETCH datecursor into v_date;
IF datecursHandler THEN
LEAVE datecurs;
END IF;
Block2: BEGIN
declare sensorCursor CURSOR for
select distinct sensor from sensorTable ;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET sensorCursHandler = TRUE;
Open sensorCursor;
senscurs: loop
FETCH sensorCursor into v_sensor;
IF sensorCursHandler THEN
SET sensorCursHandler = false;
LEAVE senscurs;
END IF;
Insert into temptable(
sensorValue,
DateID,
TimeID,
TotalCount,
TotalDistinctCount
)
SELECT
sensor AS sensorValue,
DATE_FORMAT(firstdate, '%Y%m%d') AS DateID,
HOUR(firstdate) + 1 AS TimeID,
COUNT(*) AS totalcount,
COUNT(DISTINCT sensor) AS sensordistinctcount
FROM
(SELECT
sensor AS sensor,
first_seen AS DeviceFirstSeen,
last_seen AS DeviceLastSeen,
DATE_FORMAT(FROM_UNIXTIME(first_seen), '%Y/%m/%d %k:%i:%s.%f') AS firstdate,
DATE_FORMAT(FROM_UNIXTIME(last_seen), '%Y/%m/%d %k:%i:%s.%f') AS lastdate,
FROM
sensorTable
INNER JOIN sensorTable2 ON sensorTable.ID = sensorTable2.ID
WHERE sensorTable.DeviceFirstSeen BETWEEN date_format(date_sub(date,interval 1 day),'%Y-%m-%d 15:00:00') AND date_format(date,'%Y-%m-%d 14:59:59')) a
GROUP BY DATE_FORMAT(firstdate, '%Y%m%d') , HOUR(firstdate) + 1;
end loop senscurs;
close sensorCursor;
END Block2;
END loop datecurs;
close datecursor;
END Block1;
END