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Which join yields more records?
Inner Join
Inner Join can for sure return more records than the records of the table. Inner join returns the results based on the condition specified in the JOIN condition. If there are more rows that satisfy the condition (as seen in query 2), it will return you more results.
Can LEFT join result in more rows?
Left joins can increase the number of rows in the left table if there are multiple matches in the right table. Left joins can increase the number of rows in the left table if there are multiple matches in the right table. Inner join returns the results based on the condition specified in the JOIN condition.
Does inner join create duplicates?
4 Answers. BNO-CSCcode contains duplicates. You are joining the first record of Things to both records of Mapp , then the second record of Things joins to both records of Mapp . If you want to join these together, you need some unique way of identifying the rows between the tables.
How can the left join return more results than the unjoined query?
Each row in the first table may match more than one row in the second table. A little demo is on SQL Fiddle here. Your problem is not linked to you adding restrictions but with the JOIN. When a row from table l has for instance 3 corresponding rows in c, three rows would be added to the result set.
Can a table have more records than an inner join?
Inner Join can for sure return more records than the records of the table. Inner join returns the results based on the condition specified in the JOIN condition. If there are more rows that satisfy the condition (as seen in query 2), it will return you more results. Reference: Introduction to Join – Visual Explanation.
Why does left join increase number of rows?
If there are matches though, it will still return all rows that match, therefore, one row in LEFT that matches two rows in RIGHT will return as two ROWS, just like an INNER JOIN.
How many records can a LEFT OUTER JOIN return?
The number of records in the left table is the minimum number of records it will return. If the right table has two records that match to one record in the left table, it will return two records. In response to your postscript, that depends on what you would like.