Wrong MySQL query result when accessing through Matlab

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Rodrigo Cerda 2021-9-11

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1451419-wrong-mysql-query-result-when-accessing-through-matlab

编辑： Rodrigo Cerda 2021-9-12

I'm accessing MySQL through Matlab, using the following code:

dbName      = 'dbName' ;
DB.(dbName) = database(dbName,'user','password');
 
openDateTimeStr = '2006-03-17 00:00:00';
timeZoneOpen    = 'GMT';
 
queryStr   = ['SELECT CONVERT_TZ(''' openDateTimeStr ''', ''' timeZoneOpen ''', ''GMT'')'];
 
setdbprefs('datareturnformat', 'cellarray')
curs     = exec(DB.(dbName), queryStr);
curs     = fetch(curs);
result   = curs.Data;
close(curs);

and I get the following result, which is 1 hour earlier than what it should be:

result = 1×1 cell array
        {'2006-03-16 23:00:00.0'}

But when I type the exact same query directly into MySQL Workbench, I get the correct result:

SELECT CONVERT_TZ('2006-03-17 00:00:00', 'GMT', 'GMT')  
      -> '2006-03-17 00:00:00'

On the other hand, if I do the same request but for an earlier date (eg: 2006-01-06) both queries (Matlab and MySQL Workbench) return the same (correct) result.

Hence it seems to me like a sort of daylight savings issue that's generating a problem when I access MySQL through Matlab, but not when I access MySQL through it's Workbench.

Any ideas on what might be going on? and how to fix this?