sqlite does not order greek characters correctly

[Nikos Platis]

I tried to order a table by a column containing greek strings and I found
out that sqlite does not sort them correctly. It probably uses the order of
greek characters in the Unicode table, while the correct order is vastly
different.

Here is the correct order of greek characters (mixed case) as produced by
LibreOffice Calc:

α Α ά Ά β Β γ Γ δ Δ ε Ε έ Έ ζ Ζ η Η ή Ή θ Θ ι Ι ί Ί ϊ Ϊ ΐ κ Κ λ Λ μ Μ ν Ν ξ
Ξ ο Ο ό Ό π Π ρ Ρ σ Σ τ Τ υ Υ ύ Ύ ϋΫ ΰ φ Φ χ Χ ψ Ψ ω Ω ώ Ώ

Upper case letters are sorter right after the respective lower case ones,
and, most importantly, accented vowels are sorted right after the
non-accented ones.

Here is the same list of characters as ordered by sqlite:

Ά Έ Ή Ί Ό Ύ Ώ ΐ Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω Ϊ Ϋ ά έ ή ί
ΰ α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ τ υ φ χ ψ ω ϊ ϋ ό ύ ώ

It is obvious that the most problematic point is the ordering of accented
letters, which it totally wrong.

Unfortunately, this ordering of greek characters is useless in practice, so
the correctly behavior should be implemented.

Using sqlite 3.8.1 under Linux.


Nikos Platis

[Constantine Yannakopoulos]

Post by Nikos Platis
Unfortunately, this ordering of greek characters is useless in practice, so
the correctly behavior should be implemented.

You can implement your own CI-AI greek collation and use it in your columns
that contain greek text. It really isn't that hard to do. See these links:

http://www.sqlite.org/c3ref/create_collation.html
http://www.sqlite.org/c3ref/collation_needed.html

[Simon Slavin]

Post by Nikos Platis
I tried to order a table by a column containing greek strings and I found
out that sqlite does not sort them correctly. It probably uses the order of
greek characters in the Unicode table, while the correct order is vastly
different.

If you're not already using it, please take a look at the International Components for Unicode:

<http://www.sqlite.org/src/artifact?ci=trunk&filename=ext/icu/README.txt>

It's a compilation option.

Simon.

[jose isaias cabrera]

"Simon Slavin" wrote...

Post by Simon Slavin

Post by Nikos Platis
I tried to order a table by a column containing greek strings and I found
out that sqlite does not sort them correctly. It probably uses the order of
greek characters in the Unicode table, while the correct order is vastly
different.

If you're not already using it, please take a look at the International
<http://www.sqlite.org/src/artifact?ci=trunk&filename=ext/icu/README.txt>
It's a compilation option.
Simon.

Hi Simon.

Will this ever be implemented in the normal sqlite DLL? That would be
wonderful. Thanks.

josé

[Simon Slavin]

Post by jose isaias cabrera
"Simon Slavin" wrote...

Post by Simon Slavin
<http://www.sqlite.org/src/artifact?ci=trunk&filename=ext/icu/README.txt>

Hi Simon.
Will this ever be implemented in the normal sqlite DLL? That would be wonderful. Thanks.

It's not normal to use the API using a DLL. Normally you compile whatever you need into your own code. But if you're using an existing DLL you will have to consult whoever makes that DLL about what they include in it.

Simon.

[jose isaias cabrera]

"Simon Slavin" wrote...

Post by Simon Slavin

Post by jose isaias cabrera
"Simon Slavin" wrote...

Post by Simon Slavin
If you're not already using it, please take a look at the International
<http://www.sqlite.org/src/artifact?ci=trunk&filename=ext/icu/README.txt>

Hi Simon.
Will this ever be implemented in the normal sqlite DLL? That would be
wonderful. Thanks.

It's not normal to use the API using a DLL. Normally you compile whatever
you need into your own code. But if you're using an existing DLL you will
have to consult whoever makes that DLL about what they include in it.

Thanks. The DLL I am using is the one provided by sqlite.org. I downloaded
it from there and that is the one I use. I am using an old D library, but I
can make those calls within my own program. Thanks.

josé

[lchishol-wUU9E3n5/m4qAMOr+]

Post by Simon Slavin
If you're not already using it, please take a look at the International
<http://www.sqlite.org/src/artifact?ci=trunk&filename=ext/icu/README.txt>
It's a compilation option.
Simon.

That README file seems to have bad example in Section 1.1, where the 1-parameter
usage examples seem inverted WRT the 2-parameter example, as follows:

upper('ABC') -> 'abc'
lower('abc') -> 'ABC'
versus:
lower('I', 'en_us') -> 'i'

Len Chisholm.

[Aleksey Tulinov]

Post by Nikos Platis
Here is the correct order of greek characters (mixed case) as produced by
α Α ά Ά β Β γ Γ δ Δ ε Ε έ Έ ζ Ζ η Η ή Ή θ Θ ι Ι ί Ί ϊ Ϊ ΐ κ Κ λ Λ μ Μ ν Ν ξ
Ξ ο Ο ό Ό π Π ρ Ρ σ Σ τ Τ υ Υ ύ Ύ ϋΫ ΰ φ Φ χ Χ ψ Ψ ω Ω ώ Ώ
Upper case letters are sorter right after the respective lower case ones,
and, most importantly, accented vowels are sorted right after the
non-accented ones.

Nikos, you could try nunicode, it won't order lower-upper-lower-upper,
but it should be able to correctly handle accents. How it works is
explained in this section:
https://bitbucket.org/alekseyt/nunicode#markdown-header-strings-collation-and-case-mapping

When i finish with Unicode tailoring (localization extension), you
should be able to implement correct collation for Greek characters.

[Niall O'Reilly]

Post by Nikos Platis
Here is the correct order of greek characters (mixed case) as produced by
α Α ά Ά β Β γ Γ δ Δ ε Ε έ Έ ζ Ζ η Η ή Ή θ Θ ι Ι ί Ί ϊ Ϊ ΐ κ Κ λ Λ μ Μ ν Ν ξ
Ξ ο Ο ό Ό π Π ρ Ρ σ Σ τ Τ υ Υ ύ Ύ ϋΫ ΰ φ Φ χ Χ ψ Ψ ω Ω ώ Ώ
Upper case letters are sorter right after the respective lower case ones,
and, most importantly, accented vowels are sorted right after the
non-accented ones.

I notice that you didn't mention final sigma explicitly, and also that
this seems (if I'm reading correctly) to occupy the Unicode code-point
just before non-final sigma (so: ... ρ ς σ τ ..., ignoring upper case).
I guess that's what you would want?

Best regards,
Niall O'Reilly