What is the effect of having WHERE 1=1 if you write this request in a script (pseudocode) :
sql = "SELECT f1,f2,f3 FROM t
WHERE 1=1" ++ restOfTheClause
Where restOfTheClause can be a list of field-names/operators/values concatenated with a AND :
restOfTheClause = [('f4','>',5), ('f5','IN(1,2,3)'), ('f10','=',1)].map(writeWherePart).join(' AND ')
Writing WHERE 1=1 allows to write simpler code because you don't have to check if your restOfTheClause is empty or not, etc.
What is the effect on performance with this clause ?
What is the difference between having WHERE 1=1 and having no where clause at all ?
I work on Oracle since a couple of months and i found i have to put WHERE 1=1 but other RDBMS accept WHERE true. As = is an operator, is there any performance differences between oracle and other RDBMS in using dummy clauses ?
Thank you