'Is it possible to select a variable of an outer query from a subquery?

Basically, I'm trying to reference the row currently being evaluated and use it in a subquery.

...
CASE WHEN [type] IN (1, 2) THEN (
      SELECT companyName FROM Company 
          WHERE id = (SELECT companyId FROM [TransactionParty] 
                      WHERE id = _this.fromTransactionPartyId))
END AS senderCompanyName 
...

Where "_this.fromTransactionPartyId" is referring to the fromtransactionPartyId column of the current row where [type] IN (1, 2). Is this possible?

sqlsecurityencryptionembeddediot


Solution 1:[1]

That's not possible. Are you trying to fetch companyName from the Company table only when it has a respective entry in the TransactionParty table? In that case, you use inner join:

Select c.CompanyName from Company c inner join TransactionParty t on c.id = t.companyId and c.fromTransactionPartyId=t.id

Solution 2:[2]

That's perfectly possible. You just need to name your identifiers correctly with the correct table like tab1.Id:

select 
  case when id in (1,2) then (SELECT value FROM tab2 
          WHERE tab2.id = (SELECT id2 FROM idreltab 
                      WHERE id1 = tab1.Id))
  else 'not in (1, 2)' end
from tab1

(I replaced your table names with tab1[unknown], tab2[Company] and IdRelTab[TransactionParty])

See this fiddle as example (in oracle, as you didn't mention a DBMS)

However, I'd try to use joins instead of subqueries as they're far more performance friendly

Solution 3:[3]

I have come across WolfSSL benchmarks several time for the purpose of comparing cryptography speed on different hardware.

They do not seem to provide data for a 16MHz micro controller, but they list a 48MHz Atmel SAMD21 based on an ARM Cortex M0 with a speed of 0.138MB/s for AES.

In comparison, an Intel(R) Core(TM) i5-6300U @ 2.4GHz is listed with a speed of 15.911 MB/s for AES-GCM.

One limitation of these benchmarks is that comparing them strictly is not possible: not much details on how they ran it (bare CPU versus "regular PC"), not always the same data provided (AES (?) for one, AES-GCM for the other).

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Muhand Jumah
Solution 2 Chrá´‰z remembers Monica
Solution 3 Lou_is

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