SQL intercepts string before arbitrary position in string

# #思路, The Intercept can judge the character position, if there are more than one, you can intercept the string after the number of bits, and then use the Len function minus the length of the string, intercept the remaining fields
Example: 01.001.005
Intercept is 01.001
Function Select Top 3
Left (Fnumber,len (fnumber)-charindex ('. ', Fnumber)-1)
, LEN (Fnumber)-charindex ('. ', Fnumber)-1 right up
, CHARINDEX ('. ', Fnumber) from the right
From T_icitem

# #或反转, but it takes two times to invert reverse
# #substring (string, start position, return length)

SQL intercepts string before arbitrary position in string