数据库表 test 字段 id name age
全角数字:123456
半角数字:123456
length和lengthb的区别:
length(123456) 6
lengthb(123456) 12
to_single_byte函数用法:
to_single_byte(123456) 123456
查找所有全角的数字:
select age from test where lengthB(age) >6
替换全角的为半角的:
update test t1 set t1.age = (select to_single_byte(t2.age) from test t2 where t1.id = t2.id)
ok!!