How can I set a NULL value with QSqlQuery::addBindValue()?

[jdent]

I have a sql string like this in QSqlQuery

"insert into BankAccountStatement_Scotia(id, fk_CompoundStatement, owner, account, isDollarAccount, initialBalance, booksBalance, retenidoDiferido, availableBalance, date, inputFile) values(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)"

what parameter can I feed addBindValue to make it represent NULL? Or do I absolutely need to change my sql string by removing the field that I want to leave NULL?

[JonB]

@jdent bool QVariant::isNull() const

[JonB]

@jdent Did you try QVariant()?

[jdent]

@JonB It actually works!!
However when reading the record instead of NULL it is represented by 0 (the field is an optional integer -- that is std::optional<int>).

So if I compare the record going in with the record read they are not the same!!

Any way around this?

Intercepting the reading from the database to represent the NULL value as a std::nullopt??

[JonB]

@jdent
I don't know, but show how you are seeing a 0? I would have hoped it would come back as QVariant() too? Of course make sure that the table actually holds a NULL and not a 0 after your INSERT.

[jdent]

@JonB You are correct. Reading the value returns QVariant{} (debugger reads (null))... But how do I check for a null value?

I tried this:

		QVariant value = rec.value(1);
		if (rec.value(1) == QVariant())
		{
			fk_CompoundStatement = std::nullopt;
		}

but the if does not return true even though value is (null) according to debugger!!

[JonB]

@jdent bool QVariant::isNull() const

[jdent]

@jdent I know: value.isNull()!!