Pass multiple postgres SQL statements in a single PGexec call - postgresql

Question

In t-sql, it's possible to run multiple select statements without a ;. Example:
select 1 select 2 is valid, and returns two datasets of 1 and 2 respectively.
In postgres, it is not possible to run multiple select statements... you need a ; delimiter otherwise you get a syntax error.
Referencing the docs: http://www.postgresql.org/docs/current/interactive/libpq-exec.html
Multiple queries sent in a single PQexec call are processed in a single transaction, unless there are explicit BEGIN/COMMIT commands included in the query string to divide it into multiple transactions.
How can I do this?
Let's say I want to run these two queries on the server: select 1 select 2: should it look like this:
begin
select 1
commit;
begin
select 2
commit
I'm ok with it only returning the last query as the result set, but I need to know that the first query was executed on the server, even if it's not returning with that result set.
Why I want to do this: I have a complex sql script that has ~6 temp tables to build that the main query will use. By delimiting the temp tables with the ; syntax, I can't schedule this script in cron to run on a schedule. If I can get the temp tables to run and the main query to access them in the same PGexec call, I'd be very very happy.

Answer 1

You don't need libpq directly, you can just use he psql front end (in cron, you might need to specify the absolute pathname for the binary)
#!/bin/sh
psql -U my_user mydb <<OMG
begin;
select tralal 1;
commit;
begin;
select domtidom 2;
commit;
OMG

Answer 2

I was able to accomplish what I was looking for with CTEs rather than temp tables... one long chain of CTEs (acting as temp tables) waterfalling into the main query.
A simple example:
with first as (
select 1 as col
),
second as (
select 2 as col
)
select * from first union all select * from second
A more complex example:
with COGS as (
select 'Product1' Vertical, 3.0 Credit, 1.00 Debit, 2.75 Blend, 4.30 Amex, 0.25 ACH union
select 'Product2', 3.1, 2.2, 2.8, 4.5, 0.25 union
),
Allocable_Card_Volume as (
select MPR.Date, sum(MPR.Card_Volume_Net_USD) Allocable_Card_Volume
from mpr_base MPR
where MPR.Gateway in ('YapProcessing') and MPR.Vertical not in ('HA-Intl','HA')
group by MPR.Date
),
COGS_Financials_Base as (
select '2013-01-31'::DATE Date , 1000 Total_COGS , 200 Homeaway , (select Allocable_Card_Volume from Allocable_Card_Volume where Date in ('2013-01-31') ) Allocable_Card_Volume union
),
Initial_COGS as (
select
MPR.Date,
sum(
case when MPR.PaymentTypeGroup in ('ACH_Scan','AmEx') then (Txn_Count * COGS.ACH) else 0 end +
case when MPR.Vertical not in ('HA') and MPR.PaymentTypeGroup in ('Card','AmEx-Processing') then
coalesce( ((Credit_Card_Net_USD - Amex_Processing_Net_USD) * COGS.Credit * 0.01),0) + coalesce((Debit_Card_Net_USD * COGS.Debit * 0.01),0) + coalesce((Amex_Processing_Net_USD * COGS.Amex * 0.01),0) + coalesce((case when TPV is null and PaymentTypeGroup in ('Card') then TPV_Billing else 0 end * COGS.Blend * 0.01),0)
when MPR.Vertical in ('HA') and MPR.PaymentTypeGroup in ('Card','AmEx-Processing') and FeePaymentType in ('PropertyPaid') then
coalesce(COGS_Financials.Homeaway,0)
else 0 end
) Initial_COGS
from
mpr_base MPR
left join COGS on COGS.Vertical = MPR.Vertical and MPR.Gateway in ('YapProcessing') and MPR.PaymentTypeGroup not in ('Cash')
left join COGS_Financials_Base COGS_Financials on MPR.Date = COGS_Financials.Date and MPR.Gateway in ('YapProcessing') and MPR.PaymentTypeGroup in ('Card')
where MPR.Gateway in ('YapProcessing') and MPR.Vertical not in ('HA-Intl') and MPR.PaymentTypeGroup not in ('Cash')
group by
MPR.Date
),
COGS_Financials as (
select
COGS_Financials_Base.*, (COGS_Financials_Base.Total_COGS - Initial_COGS.Initial_COGS) Allocation
from
COGS_Financials_Base
join Initial_COGS on COGS_Financials_Base.Date = Initial_COGS.Date
),
MPR as (
select
MPR.Date,MPR.Gateway,MPR.Vertical, MPR.ParentAccountId, MPR.ParentName ,
MPR.PaymentTypeGroup ,
sum(TPV_USD) TPV_USD,
sum(TPV_Net_USD) TPV_Net_USD,
sum(Revenue_Net_USD) Revenue_Net_USD ,
sum(coalesce(
case when MPR.PaymentTypeGroup in ('ACH_Scan','AmEx') then (Txn_Count * COGS.ACH) else 0 end +
case when MPR.Vertical not in ('HA') and MPR.PaymentTypeGroup in ('Card','AmEx-Processing') then
coalesce( ((Credit_Card_Net_USD - Amex_Processing_Net_USD) * COGS.Credit * 0.01),0) + coalesce((Debit_Card_Net_USD * COGS.Debit * 0.01),0) + coalesce((Amex_Processing_Net_USD * COGS.Amex * 0.01),0) + coalesce((case when TPV is null and PaymentTypeGroup in ('Card') then TPV_Billing else 0 end * COGS.Blend * 0.01),0)
+(coalesce( ( ( cast(Card_Volume_Net_USD as decimal(18,2) ) / cast(COGS_Financials.Allocable_Card_Volume as decimal(18,2)) ) * COGS_Financials.Allocation ), 0) ) -- Excess
when MPR.Vertical in ('HA') and MPR.PaymentTypeGroup in ('Card','AmEx-Processing') and MPR.FeePaymentType in ('PropertyPaid') then coalesce(COGS_Financials.Homeaway,0)
else 0
end,0)
) COGS_USD,
sum(Txn_Count) Txn_Count
from
mpr_Base MPR
left join COGS on COGS.Vertical = MPR.Vertical and MPR.Gateway in ('YapProcessing') and MPR.PaymentTypeGroup not in ('Cash')
left join COGS_Financials on MPR.Date = COGS_Financials.Date and MPR.Gateway in ('YapProcessing') and MPR.PaymentTypeGroup in ('Card','AmEx-Processing')
where
MPR.Date in ('2016-02-29')
group by
MPR.Date,MPR.Gateway,MPR.Vertical , MPR.ParentAccountId ,MPR.ParentName,
MPR.PaymentTypeGroup
)
select
Vertical,
sum(TPV_USD)::money as TPV_USD,
sum(Revenue_Net_USD)::money as Revenue_Net_USD,
sum(COGS_USD)::money COGS_USD,
round((sum(Revenue_Net_USD)-sum(COGS_USD))/sum(Revenue_Net_USD)*100,2) Accounting_Margin
from
MPR
where Date in ('2016-02-29')
group by
Vertical
union all
select
'Total' ,
sum(TPV_USD)::money as TPV_USD,
sum(Revenue_Net_USD)::money as Revenue_Net_USD,
sum(COGS_USD)::money COGS_USD,
round((sum(Revenue_Net_USD)-sum(COGS_USD))/sum(Revenue_Net_USD)*100,2) Accounting_Margin
from
MPR
where Date in ('2016-02-29')
I said it would be complex :-)

Answer 3

From your answer, you could also do this
SELECT * FROM a
UNION ALL
SELECT * FROM b
UNION ALL
SELECT * FROM c
...