详细说明 select * from ( select url, (length(url) - length(replace(url, ".", ""))) as UUU from wzzjnet_site WHERE url not like 'http://www%' limit 0,1000) a where uuu=1;
select url, (length(url) - length(replace(url, ".", ""))) as UUU from wzzjnet_site WHERE url not like 'http://www%' and (length(url) - length(replace(url, ".", "")))=1 limit 0,1000;
select * from (
select url, (length(url) - length(replace(url, ".", ""))) as UUU from wzzjnet_site WHERE url not like 'http://www%'
limit 0,1000) a where uuu=1;
from wzzjnet_site
WHERE url not like 'http://www%' and (length(url) - length(replace(url, ".", "")))=1
limit 0,1000;