ORACLE TRIM function -
suppose column defined as:
col varchar2(5)
- if
col='x'
true
; - if
trim(col)=trim('x')
true
; - but if col contains
' '
, iftrim(col)=trim(' ')
false
;
why?
thanks
oracle doesn't support empty strings ''; oracle uses null instead (whenever result should empty string you'll null in fact). since
null = null -- <- null (and not true)
your formula
trim(col) = trim(' ') -- <- equals "null = null"
is null (and not true) too
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