Sub query MySql with MIN()

Question

With QT5.15.1, Windows 10 64, last Mysql connect:

My query :

SELECT ata, description, min(duedate) as duedate, tbocalendar, tbocalendar2, table_name FROM (SELECT ata, description, duedate1 AS duedate, tbocalendar, tbocalendar2, 'part_log' as table_name FROM part_log WHERE tbocalendar!= 'N/A' AND removed = 'FALSE' AND activecheck = 'ACTIVE' AND immatriculation=? UNION SELECT ata, description, duedate2 AS duedate, tbocalendar, tbocalendar2, 'part_log' as table_name FROM part_log WHERE removed = 'FALSE' AND activecheck = 'ACTIVE' AND immatriculation=? UNION SELECT ata, element as description, echeance AS duedate,  tbocalendar, 'N/A' as tbocalendar2, 'ltr_log' as table_name  FROM ltr_log  WHERE date_cloture = 'N/A' AND echeance !='N/A' AND immatriculation=?) WHERE substr(description,1,5)!='Carte' LIMIT 1

This return an error that I don't understand:

#1064 - Erreur de syntaxe près de 'LIMIT 0, 25' à la ligne 1

why all my queries using subqueries like below return this error?:

Select xxx,yyyy from (Select xxx,yyyy from table_name union all Select xxx,yyyy from table_name1)

I need to have a query like : Select MIN(date_example) FROM (SELECT date1 as date_example from table1 UNION ALL SELECT date2 as date_example from table2)

All theses queries was working fine with sqlite, but they are not working with mysql and error without any explanations doesn't help me...

Thank you very much for your help guys ;-)

Answer 1

You should define an alias for the new table you constructed:

Select 
   MIN(tableAlias.date_example) 
FROM 
   (
   SELECT 
      date1 as date_example 
   from table1 
   UNION ALL 
   SELECT date2 as date_example from table2
   ) As tableAlias