To sum up values from different tables in PostgreSQL, you can use the JOIN keyword to combine the tables and then use the SUM() function to calculate the total value. By joining the tables on a common key, you can aggregate the values from the different tables in a single query. This allows you to easily calculate the sum of values from multiple tables by grouping them together with the common key. Additionally, you can use WHERE clauses to filter the data and only sum up values that meet certain conditions. Overall, utilizing joins and aggregate functions like SUM() can help you efficiently calculate the sum of values from different tables in PostgreSQL.

## How to eliminate redundant information while summing values from distinct tables in PostgreSQL?

To eliminate redundant information while summing values from distinct tables in PostgreSQL, you can use the UNION ALL or UNION operator to combine the results of the queries from the distinct tables and then use the SUM function to calculate the total sum of the values. Here's an example:

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(SELECT SUM(column_name) FROM table1) UNION ALL (SELECT SUM(column_name) FROM table2); |

This will give you the total sum of the values from both tables without any redundant information.

## How to perform calculations on aggregated results from multiple tables in PostgreSQL?

To perform calculations on aggregated results from multiple tables in PostgreSQL, you can use subqueries or JOIN statements in combination with aggregate functions.

Here is an example of how you can perform calculations on aggregated results from multiple tables in PostgreSQL:

- Using Subqueries:

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SELECT (SELECT SUM(amount) FROM table1) as total_amount_table1, (SELECT AVG(sales) FROM table2) as avg_sales_table2 |

- Using JOIN:

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SELECT SUM(t1.amount) as total_amount_table1, AVG(t2.sales) as avg_sales_table2 FROM table1 t1 JOIN table2 t2 ON t1.id = t2.id |

By using subqueries or JOIN statements along with aggregate functions like SUM, AVG, etc., you can perform calculations on aggregated results from multiple tables in PostgreSQL.

## How to access and sum values from temporary tables in PostgreSQL?

To access and sum values from temporary tables in PostgreSQL, you can follow these steps:

- Create a temporary table and insert data into it:

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CREATE TEMP TABLE temp_table ( id SERIAL PRIMARY KEY, value INTEGER ); INSERT INTO temp_table (value) VALUES (10), (20), (30); |

- Query the temporary table to sum the values:

```
1
``` |
```
SELECT SUM(value) FROM temp_table;
``` |

This query will return the sum of the values in the temporary table. You can also perform other operations on the data in the temporary table using standard SQL queries.

Remember that temporary tables are only accessible within the session they were created in, and they will be automatically dropped when the session ends.

## How to apply filters while summing data from multiple tables in PostgreSQL?

You can apply filters while summing data from multiple tables in PostgreSQL by using the JOIN clause along with WHERE clause to specify the conditions for filtering the data. Here is an example of how you can sum data from multiple tables with filters:

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SELECT SUM(table1.column1 + table2.column2) AS total_sum FROM table1 JOIN table2 ON table1.id = table2.id WHERE table1.column3 = 'value1' AND table2.column4 > 100; |

In this example, we are summing column1 from table1 and column2 from table2 where the id column is the same in both tables. We are also applying filters to only include rows where column3 in table1 has the value 'value1' and column4 in table2 is greater than 100.

You can adjust the tables, columns, and filter conditions based on your specific requirements.