I have a 1 table query which returns less rows than when I have a 2 table query using an implicit inner join or an explicit left join.

Select some, fields
From table1
Where part like '123%'
/* returns 2225 rows */

Select activePart, some, fields
From table1, table2
Where part like '123%'
and part = activePart
/* implicit inner join returns 2270 rows */

Select activePart, some, fields
From table1 left join table2
On part = activePart
Where part like '123%'
/* explicit left join also returns 2270 rows */

Fields part and activePart are not in table2 and table1 respectively.

I assume I am forgetting something basic this friday. Why would I get more rows from the above? I might expect more rows from an outer join. Am I writing an outer join?

After a quick break in the john, I'm thinking perhaps table2 is not holding unique "part"s as I was told it would. But I'll post this for your thoughts before I check on that, in case you have other insights.


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