How to Use Reverse Like In Oracle?

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To use reverse like in Oracle, you can use the LIKE operator along with the reverse function. The reverse function in Oracle is used to reverse a string.


For example, if you want to find all the rows in a table where a certain column ends with a specific string, you can use the reverse function in conjunction with the LIKE operator.


Here is an example query:


SELECT * FROM table_name WHERE reverse(column_name) LIKE reverse('%specific_string%');


This query will return all the rows in the table where the specified column ends with the specific string, regardless of the case. The reverse function is useful in situations where you need to search for patterns at the end of a string in Oracle.

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How to handle NULL values in reverse like queries in Oracle?

When handling NULL values in reverse-like queries in Oracle, you can use the NVL function to replace the NULL values with a specific value before executing the query.


Here is an example:

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SELECT column_name
FROM table_name
WHERE NVL(column_name, 'replacement_value') NOT LIKE '%search_string%';


In this query, the NVL function is used to replace any NULL values in column_name with 'replacement_value' before performing the LIKE comparison in the WHERE clause. This ensures that NULL values do not interfere with the reverse-like search.


Alternatively, you can use the COALESCE function instead of the NVL function to achieve the same result:

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SELECT column_name
FROM table_name
WHERE COALESCE(column_name, 'replacement_value') NOT LIKE '%search_string%';


By using the NVL or COALESCE functions to handle NULL values before executing reverse-like queries, you can ensure accurate results without any unexpected NULL-related issues.


How to use reverse like in a join condition in Oracle?

To use the reverse function in a join condition in Oracle, you can simply apply the reverse function to the column you are referencing in the join condition.


Here is an example of how you can use the reverse function in a join condition in Oracle:

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SELECT t1.column1, t2.column2
FROM table1 t1
JOIN table2 t2 ON reverse(t1.column1) = t2.column2;


In this example, we are joining table1 and table2 on the condition that the reversed value of column1 in table1 is equal to column2 in table2.


You can customize the reverse function based on your requirements and use it in various join conditions in Oracle.


What is the cost-based optimizer's approach to reverse like in Oracle?

In Oracle, the cost-based optimizer's approach to reverse optimization involves evaluating various execution plans for a SQL statement and choosing the plan with the lowest cost. The optimizer considers factors such as the estimated cost of disk I/O, CPU usage, and memory usage for each potential plan. By selecting the plan with the lowest cost, the optimizer aims to improve the overall performance of the query. Reverse optimization in Oracle involves iteratively trying different access paths, join methods, and other optimization techniques to find the most efficient plan for a given query.

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