I can't figure out when to put the selection criteria as part of the join and when it should be part of the where clause.
for example - what is the difference between
Select table1.field1, table2.field2, table3.field3 from table1 Left Join table2 on table1.field1 = table2.field1 and table2.field2 <> 'abc' Left Join table3 on table1.field1 = table3.field1
AND
Select table1.field1, table2.field2, table3.field3 from table1 Left Join table2 on table1.field1 = table2.field1 Left Join table3 on table1.field1 = table3.field1 WHERE table2.field2 <> 'abc' or table2.field1 is null
How does one know when to use one over the other?? I get different results depending on where I put the selection criteria and don't understand why.
JOIN LOGIC
Posted - 01/31/2013 : 17:39:31
