日期控件
-------
select * from A
where 1=1
${IF(LEN(START)=0,"","AND date>= '"+START+"'")}
${IF(LEN(END)=0,"","AND date <= '"+END+"'")}
${if(and(LEN(START)=0,LEN(end)=0)," and date is not null and date<>''","")}
加一个日期 is not null 的判断条件