How to Join Two Tables From Two Columns In Oracle?

To join two tables from two columns in Oracle, you can use the JOIN keyword in your SQL query. You will need to specify the tables you want to join, as well as the columns from each table that you want to use for the join. For example, if you have two tables named table1 and table2, and you want to join them on columns column1 and column2, you can use the following query:

SELECT * FROM table1 JOIN table2 ON table1.column1 = table2.column2;

This will return a result set that includes all columns from both tables where the values in column1 from table1 match the values in column2 from table2.

How to join tables with duplicate values in Oracle?

To join tables with duplicate values in Oracle, you can use the following SQL statement:

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SELECT t1.column1, t2.column2
FROM table1 t1
JOIN table2 t2 ON t1.common_column = t2.common_column;

In the above statement, replace table1 and table2 with the names of the tables you want to join, column1 and column2 with the columns you want to select from each table, and common_column with the column that both tables have in common and contain duplicate values.

This will join the two tables on the common column and return the selected columns from each table where the common column values match. Duplicate values in the common column will be included in the result set.

How to join tables from different schemas in Oracle?

To join tables from different schemas in Oracle, you can use the fully qualified table name in your SELECT statement.

Here is an example of how to join tables from different schemas in Oracle:

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SELECT a.column1, b.column2
FROM schema1.table1 a
JOIN schema2.table2 b ON a.column3 = b.column4;

In this example, we are selecting data from columns in table1 in schema1 and table2 in schema2. We use the fully qualified table names (schema.table) to specify the tables we are querying from and join them using the JOIN keyword on the specified columns.

How to combine data from two columns in Oracle?

To combine data from two columns in Oracle, you can use the CONCAT function or the double pipe || operator.

Here's an example of using the CONCAT function:

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SELECT CONCAT(column1, ' ', column2) AS combined_data 
FROM your_table;

Here's an example of using the double pipe || operator:

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SELECT column1 || ' ' || column2 AS combined_data
FROM your_table;

In both cases, column1 and column2 are the names of the columns you want to combine, and your_table is the name of the table containing these columns. The AS keyword is used to give a name to the combined data column in the result set.

You can also add other characters or strings in between the columns that you want to combine, such as spaces, commas, or other characters, by including them within the quotes or between the || operators.