将两个SQL查询合并为一个

Question

I have two sql queries (which both work independently) that I am trying to combine:

Query #1:

select 
    N1."DateAndTime",
    N0."Ration" 
from 
    (("dbo"."AnimalFeedDailyConsumption" N0 
inner join 
    "dbo"."AnimalHistoricalData" N1 on (N0."OID" = N1."OID")) 
left join 
    "dbo"."BasicAnimal" N2 on (N1."BasicAnimal" = N2."OID"))
where 
    (N1."LactationNumber" = 4) and (N1."GCRecord" is null and (N2."Number" = 511))

Query #2:

select 
   N2."Number",
   N1."DIM",
   N1."DateAndTime",
   N1."LactationNumber",
   N0."TotalYield"
from 
   (("dbo"."DailyMilk" N0 
inner join 
   "dbo"."AnimalHistoricalData" N1 on (N0."OID" = N1."OID")) 
left join 
   "dbo"."BasicAnimal" N2 on (N1."BasicAnimal" = N2."OID"))
where 
   (N1."LactationNumber" = 4) and (N1."GCRecord" is null and (N2."Number" = 511))

I tried this which resulted in nulls for 'Ration':

select 
    N2."Number",
    N1."DIM",
    N1."DateAndTime",
    N1."LactationNumber",
    N0."TotalYield",
    N3."Ration"
from 
    (("dbo"."DailyMilk" N0 
inner join 
    "dbo"."AnimalHistoricalData" N1 on (N0."OID" = N1."OID")) 
left join 
    ("dbo"."AnimalFeedDailyConsumption" N3 
inner join 
    "dbo"."AnimalHistoricalData" N1 on (N3."OID" = N1."OID"))
left join 
    "dbo"."BasicAnimal" N2 on (N1."BasicAnimal" = N2."OID"))
where 
    (N1."LactationNumber" = 4) and (N1."GCRecord" is null and (N2."Number" = 511))

So then I tried this which also resulted in nulls for 'Ration':

select 
   N2."Number",
   N1."DIM",
   N1."DateAndTime",
   N1."LactationNumber",
   N0."TotalYield",
   N3."Ration"
from
   (("dbo"."DailyMilk" N0 
inner join 
   "dbo"."AnimalHistoricalData" N1 on (N0."OID" = N1."OID")) 
left join 
   "dbo"."AnimalFeedDailyConsumption" N3 on (N3."OID" = N1."OID")
left join 
   "dbo"."BasicAnimal" N2 on (N1."BasicAnimal" = N2."OID"))
where 
   (N1."LactationNumber" = 4) and (N1."GCRecord" is null and (N2."Number" = 511))

Answer 1

This is hard to answer because I don't know the relationships between your tables. In your "working" queries, you are testing for conditions on the RIGHT table (N2), which you joined with LEFT OUTER because it is optional - perhaps this is correct, but doesn't look right.

How about this, with all joins converted to inner joins?:

select 
  N2."Number",
  N1."DIM",
  N1."DateAndTime",
  N1."LactationNumber",
  N0."TotalYield",
  N3."Ration"
from "dbo"."DailyMilk" N0 
inner join "dbo"."AnimalHistoricalData" N1       on N0."OID" = N1."OID" 
inner join "dbo"."AnimalFeedDailyConsumption" N3 on N3."OID" = N1."OID"
inner join "dbo"."BasicAnimal" N2                on N1."BasicAnimal" = N2."OID"
where N1."LactationNumber" = 4 
and   N1."GCRecord" is null 
and   N2."Number" = 511

Style Comment: BTW it is hard (for me) to understand which table is N0, N1, N3 & N3. Why not alias them as BA, AHD, DM and AFDC? Also, too many (redundant) braces.

Note: I can't test this out since I don't have your tables or data. How about you create a SQLfiddle?