[BUGS] substring problem

[Sh A Guru Prasad]

 select trn_id,substr(hoa_id,1,13) from  tbill_master where 
substr(hoa
_id,1,13)='2202031040006';
     trn_id     |    substr
----------------+---------------
 25001203000416 | 2202031040006
 25001203000417 | 2202031040006
 25001203000418 | 2202031040006
 25001203000419 | 2202031040006
 25001203000420 | 2202031040006
 25001203000421 | 2202031040006
 25001203000422 | 2202031040006
 25001203000536 | 2202031040006  

and
 select trn_id,substr(hoa_id,0,14) from  tbill_master where 
substr(hoa
_id,0,14)='2202031040006';
     trn_id     |    substr
----------------+---------------
 25001203000416 | 2202031040006
 25001203000417 | 2202031040006
 25001203000418 | 2202031040006
 25001203000419 | 2202031040006
 25001203000420 | 2202031040006
 25001203000421 | 2202031040006
 25001203000422 | 2202031040006
 25001203000536 | 2202031040006  
both give the same result how? Is it query problem or 
postgress substring problem please clarify.



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