[Info-ingres] Micro-madness

[Martin Bowes]

Hi All,

Can someone please explain this one…please use small words…

My Linux installation is an ISO-8859-1 charset. We have a  table which has an nvarchar(20) column.

Now the Greek mu symbol is U+00B5, a capital-A with a circumflex is 00C2, The ¼ is U+00BC, and a capital-I with a circumflex is U+00CE.

And in terminal monitor connection, how does this work…
select U&'\00c2', U&'\00b5', U&'\00c2\00b5'\g
┌──────┬──────┬──────┐
│col1  │col2  │col3  │
├──────┼──────┼──────┤
│▒     │▒     │µ    │
└──────┴──────┴──────┘
(1 row)
select u&'\00ce', u&'\00bc', u&'\00ce\00bc'\g
┌──────┬──────┬──────┐
│col1  │col2  │col3  │
├──────┼──────┼──────┤
│▒     │▒     │μ    │
└──────┴──────┴──────┘
(1 row)

So two weird codes have both combined to make a mu. I didn’t just invent these. I got them from two distinct data sets which were being compared.

And they are clearly not the same thing.

create table test(id integer1, a nvarchar(20));

insert into test values (1, U&'\00c2\00b5'), (2, U&'\00ce\00bc');
select * from test\g
┌──────┬────────────────────────────────────────┐
│id    │a                                       │
├──────┼────────────────────────────────────────┤
│     1│µ                                      │
│     2│μ                                      │
└──────┴────────────────────────────────────────┘
(2 rows)

select a, count(1) from test group by a\g
┌────────────────────────────────────────┬─────────────┐
│a                                       │col2         │
├────────────────────────────────────────┼─────────────┤
│µ                                      │            1│
│μ                                      │            1│
└────────────────────────────────────────┴─────────────┘
(2 rows)

So could someone please explain this, and also how I can write some code which will say these two mu’s are the same thing.

Marty
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