如何在强制转换后修复溢出？

Question

我有以下查询

COS(RADIANS(cast(nullif(dblat, '') as double precision)))

我收到以下错误：

Overflow, 4.818114344e-315 (Double valid range 2.225074e-308 to 1.797693e+308)

Detail: 
-----------------------------------------------
error:  Overflow, 4.818114344e-315 (Double valid range 2.225074e-308 to 1.797693e+308)
code:      1207
context:   Value: '4.818114344e-315', Character: '4'
query:     9094308
location:  :0
process:   query1_66 [pid=0]

请帮我解决这个问题