Vous trouverez ci-dessous trois implémentations distinctes pour chacun de SQL Server, MySQL et Oracle. Aucun n'utilise (ou ne peut) la même approche, il ne semble donc pas y avoir de moyen croisé entre les SGBD de le faire. Pour MySQL et Oracle, seul le test d'entier simple est affiché; pour SQL Server, le test numérique complet est affiché.
Pour SQL Server :notez que isnumeric('.') renvoie 1.. mais il ne peut pas être converti en flottant. Certains textes comme '1e6' ne peuvent pas être convertis directement en numérique, mais vous pouvez passer par float, puis numérique.
;with tmp(x) as (
select 'db01' union all select '1' union all select '1e2' union all
select '1234' union all select '' union all select null union all
select '1.2e4' union all select '1.e10' union all select '0' union all
select '1.2e+4' union all select '1.e-10' union all select '1e--5' union all
select '.' union all select '.123' union all select '1.1.23' union all
select '-.123' union all select '-1.123' union all select '--1' union all
select '---1.1' union all select '+1.123' union all select '++3' union all
select '-+1.123' union all select '1 1' union all select '1e1.3' union all
select '1.234' union all select 'e4' union all select '+.123' union all
select '1-' union all select '-3e-4' union all select '+3e-4' union all
select '+3e+4' union all select '-3.2e+4' union all select '1e1e1' union all
select '-1e-1-1')
select x, isnumeric(x),
case when x not like '%[^0-9]%' and x >'' then convert(int, x) end as SimpleInt,
case
when x is null or x = '' then null -- blanks
when x like '%[^0-9e.+-]%' then null -- non valid char found
when x like 'e%' or x like '%e%[e.]%' then null -- e cannot be first, and cannot be followed by e/.
when x like '%e%_%[+-]%' then null -- nothing must come between e and +/-
when x='.' or x like '%.%.%' then null -- no more than one decimal, and not the decimal alone
when x like '%[^e][+-]%' then null -- no more than one of either +/-, and it must be at the start
when x like '%[+-]%[+-]%' and not x like '%[+-]%e[+-]%' then null
else convert(float,x)
end
from tmp order by 2, 3
Pour MySQL
create table tmp(x varchar(100));
insert into tmp
select 'db01' union all select '1' union all select '1e2' union all
select '1234' union all select '' union all select null union all
select '1.2e4' union all select '1.e10' union all select '0' union all
select '1.2e+4' union all select '1.e-10' union all select '1e--5' union all
select '.' union all select '.123' union all select '1.1.23' union all
select '-.123' union all select '-1.123' union all select '--1' union all
select '---1.1' union all select '+1.123' union all select '++3' union all
select '-+1.123' union all select '1 1' union all select '1e1.3' union all
select '1.234' union all select 'e4' union all select '+.123' union all
select '1-' union all select '-3e-4' union all select '+3e-4' union all
select '+3e+4' union all select '-3.2e+4' union all select '1e1e1' union all
select '-1e-1-1';
select x,
case when x not regexp('[^0-9]') then x*1 end as SimpleInt
from tmp order by 2
Pour Oracle
case when REGEXP_LIKE(col, '[^0-9]') then col*1 end
