Oy, reverting would be a mistake. It's something about that system, or WB/SqlYog, or a setting.
Does the query throw this error in the mysql client program, or in mysql shell? If so, it's a WB/Yog problem.
If not, keep increasing max_heap_table_size and tmp_table_size in increments, and monitor the rate of increase of the Created_tmp_disk_tables reported by SHOW GLOBAL STATUS, compared to Created_tmp_tables (temp tables that did not use disk). As the allowed tmp table size is able to hold a greater percentage of temp tables created, you should start to see the ratio of on-disk temp tables to in-memory temp tables decrease.
If that fails, does the subquery ...
select w.weekend, d2.code as family, d2.amount
from weekendings w
join dr02 d2 on (w.weekend >= d2.date and d2.t1 <> "g")
or (w.weekend >= d2.weekend and d2.t1 = "g")
where d2.amount is not null;
also throw the error?
If not, does this query throw it?
with cte as (
select w.weekend, d2.code as family, d2.amount
from weekendings w
join dr02 d2 on (w.weekend >= d2.date and d2.t1 <> "g")
or (w.weekend >= d2.weekend and d2.t1 = "g")
where d2.amount is not null
)
select weekend, code, sum(amount) as owing
group by weekend, code
order by weekend, code
If so, does this?
Create table tmp
select w.weekend, d2.code as family, d2.amount
from weekendings w
join dr02 d2 on (w.weekend >= d2.date and d2.t1 <> "g")
or (w.weekend >= d2.weekend and d2.t1 = "g")
where d2.amount is not null;
select weekend, code, sum(amount) as owing
from tmp
group by weekend, code
order by weekend, code
[/code]
If that also induces the error, let's see my.ini in full.