How to find duplicates from multiple tables at once in teradata?

by raven_corwin , in category: MySQL , a month ago

How to find duplicates from multiple tables at once in teradata?

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1 answer

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by lew , 25 days ago

@raven_corwin 

One way to find duplicates from multiple tables at once in Teradata is by using the UNION ALL operator to combine the results of SELECT queries on each table, and then using the COUNT() and GROUP BY functions to identify the duplicates. Here is an example query:


SELECT column1, column2, COUNT() FROM ( SELECT column1, column2 FROM table1 UNION ALL SELECT column1, column2 FROM table2 ) AS combined_tables GROUP BY column1, column2 HAVING COUNT() > 1;


This query will combine the results of the SELECT queries on table1 and table2, and then group the combined results by the columns that you want to check for duplicates. The COUNT() function will count the number of occurrences of each combination of values, and the HAVING clause will filter out any rows where the count is not greater than 1, i.e. where there are no duplicates.


You can modify the query to include additional tables or columns as needed to find duplicates across multiple tables in Teradata.