# Thread: 3 Table Massive Query

1. Registered User
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## Unanswered: 3 Table Massive Query

I have 3 tables(1=165000 records, 2=11500 records, 3=14000 records). I am having trouble retrieving data which is duplicate in all three tables. Can anyone help? I am using both Access and SqL yet no results.
Thanks

2. Registered User
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## Re: 3 Table Massive Query

If structure of tables is similar too then use UNION clause to accomplish the resultset.

dollar

Originally posted by Angela
I have 3 tables(1=165000 records, 2=11500 records, 3=14000 records). I am having trouble retrieving data which is duplicate in all three tables. Can anyone help? I am using both Access and SqL yet no results.
Thanks

3. Registered User
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Yes, you can use UNION then use distinct

-Ljrong

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## Re: 3 Table Massive Query

Originally posted by Angela
I have 3 tables(1=165000 records, 2=11500 records, 3=14000 records). I am having trouble retrieving data which is duplicate in all three tables. Can anyone help? I am using both Access and SqL yet no results.
Thanks
Could you post your table structure (using DESCRIBE) and an example of what you try to do with example results?

5. Registered User
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Hi,

No need of using DISTINCT, because UNION cause returns only distinct values of all tables.

Hope this helps,
Grofaty

Originally posted by ljrong
Yes, you can use UNION then use distinct

-Ljrong

6. Registered User
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## Re: 3 Table Massive Query

Hi Angela,

What kind of data would you like to get? Would you like to get rid of duplicate data or you would like to get the data witch are duplicate on two of three tables?

To get rid of duplicate data use:
select c1 from t1 UNION select c1 from t2 UNION select c1 from t3

To get duplicate data use:
select c1 from (select c1 from t1 union all select c1 from t2 union all select c1 from t3) alias group by c1 having count(*) > 1

Hope this helps,
Grofaty

Originally posted by Angela
I have 3 tables(1=165000 records, 2=11500 records, 3=14000 records). I am having trouble retrieving data which is duplicate in all three tables. Can anyone help? I am using both Access and SqL yet no results.
Thanks

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