Adding bodymass support

db/readme.md

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+## Joining to bodymass table by time
+
+Data in the bodymass table can be transformed as (for account 1):
+
+```sql
+select kilos, time as start, (case when lead(time) over (order by time asc) is null then 'infinity'::timestamptz else lead(time) over (order by time asc) end) as end from bodymass where account=1;
+```
+
+Thereby giving a table with clear timespans. Joining can then be performed by a nested table:
+
+```
+with bm_report as (
+select kilos, time as start,
+     (case when lead(time) over (order by time asc) is null 
+      then 'infinity'::timestamptz 
+      else lead(time) over (order by time asc) end) as end from bodymass
+      where account=1)
+select 
+   t.time, t.exercise, t.kilos, b.kilos as bodymass, round(100*t.kilos/b.kilos, 1) as ratio
+   from training t
+   inner join bm_report b on t.time >= b.start and t.time < b.end
+   where t.account=1 and exercise=1
+   order by 1;
+```
+
+