Doug, on Monday, November 18, 2019 02:48 PM, wrote...
>
> I'm really confused now. I don't understand the semantics of:
> SELECT IfNull('p006', Max(idate)),
> IfNull(b, 1),
> IfNull(c, 2),
> 'y',
> IfNull(e, 4),
> '2019-20-12'
> FROM t
> WHERE a = 'p006';
>
> versus this:
> SELECT (a,b,c,d,e,idate) from t where a = "p006"
>
> Doesn't the where clause that cannot be satisfied in both cases guarantee
> that no rows will
> be selected, when there are no records in the database?
Imagine this select:
SELECT 'p006',1, 2, 'y', 4, '2019-02-11';
The IfNull is bringing these values back if the 'p006' does not exists. Try
the above select in SQLite3 tool. You will get a record. Even without table.
Since the original question was how can I INSERT... this will check the table
for 'p006', if it exists, it will bring some of the data from that existing
record and insert a new one. Ihth.
josé
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