Please help me to know if I can use WHERE and HAVING both in same query?

Question

Table Name : Hist_table

 Shp_cd wt_grp  net_wt  tot_wt
   101   10       9      7
   102   20       8      2
   103   15       4      1

Factor_table

Fact_id fact_column factor
  1     wt_grp        2
  2     net_wt        5
  3     tot_wt        3

Note – this factor table contains rows as the column name of hist_table.
Now we have to update the Hist_table with the multiplied with the factors
For example wt_grp factor is 2 then we have to update all the wt_grp column of hist table as Hist_table.wt_grp * factor_table.factor
So the result should be

shpcd   wt_grp  net_wt  tot_wt
101     20        45    21
102     40        40    6
103     30        20    3

Answer 1

The WHERE clause filters on individual rows (before they are passed to the aggregate) and the HAVING clause filters on the aggregated values. It might look something like this:

select country, count(*)  
from forum_brick 
where username is not null 
group by country 
HAVING count(*) > 10 
order by count(*) DESC