CODEWITHSUNDEEP
sqloracle-database
net user
net user

Reputation: 593

Query from table based on some condition

I have a scenario like this, there are 2 tables table_1 and table_2. Both table have a common column called column_1(no foreign_Key constraints!!). Table_1 can have some extra rows which are not present in table_2(In other words, table_2 is a sub-set of table_1). I want to list all those items which are only present in table_1 but not in table_2. Kindly help in writing the sql query for the same. Thanks in advance.

Upvotes: 2

Views: 100

Answers (3)

Ankit Aggarwal
Ankit Aggarwal

Reputation: 370

select a.* from table1 a left outer join table2 b on a.col1=b.col1;

Upvotes: 0

SRIRAM
SRIRAM

Reputation: 1888

 select * from table1 
 inner join table2 on table1.column1=table2.column1

Upvotes: 1

John Woo
John Woo

Reputation: 263943

SELECT a.*
FROM   table1 a
       LEFT JOIN table2 b
           on a.column_1 = b.column_1
WHERE b.column_1 IS NULL

if those two tables are not related with each other, better add an index on table1.column_1 and table2.column_1 so that it won't require full table scan (which slows the performance)

Upvotes: 3

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