字符串拼接
select substr(t.short_name,0,3)|| '个体户' from up_merchant_info t where t.merc_num = '18030115384673';
update up_merchant_info t set t.short_name = (select substr(t.short_name,0,3)|| '个体户' from up_merchant_info t where t.merc_num = '180301153846731') where t.merc_num = '180301153846731'