How to Use Substr In Oracle?

To use the SUBSTR function in Oracle, you need to provide three arguments: the string you want to extract a substring from, the starting position of the substring, and the length of the substring.

For example, the following query would extract a substring starting at the 4th character and with a length of 3 characters from the 'Hello, World!' string: SELECT SUBSTR('Hello, World!', 4, 3) FROM dual;

This would return 'lo,' as the output. Remember that the starting position is 1-based, not 0-based, and the length cannot be negative.

How to use substr in oracle to extract characters in reverse order?

To extract characters in reverse order using the SUBSTR function in Oracle, you can follow these steps:

1. Write a SQL query with the SUBSTR function to extract characters in reverse order.
2. Use the SUBSTR function with the following syntax:

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SELECT SUBSTR(column_name, -position, 1) AS reversed_char
FROM table_name;

Replace column_name with the name of the column from which you want to extract characters, and table_name with the name of the table where the column is located.

1. Replace position with the position of the character you want to extract in reverse order. Use a negative number to count from the end of the string. For example, -1 will extract the last character, -2 will extract the second last character, and so on.
2. Run the query to extract characters in reverse order using the SUBSTR function.

For example, if you have a table called "employees" with a column "first_name" and you want to extract the characters in reverse order for the first name of each employee, you can use the following query:

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SELECT SUBSTR(first_name, -1, 1) AS reversed_char
FROM employees;

This query will extract the last character of the "first_name" column in reverse order for each employee in the "employees" table.

How to use substr in oracle to extract characters from a CLOB column?

To extract characters from a CLOB column in Oracle, you can use the SUBSTR function. Here is an example of how to extract characters from a CLOB column:

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SELECT SUBSTR(column_name, start_position, length) AS extracted_characters
FROM table_name;

In this query:

• column_name: the name of the CLOB column from which you want to extract characters.
• start_position: the position in the column from which to start extracting characters.
• length: the number of characters to extract.

For example, if you have a CLOB column named 'text_content' in a table 'documents' and you want to extract the first 100 characters from it, you can use the following query:

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SELECT SUBSTR(text_content, 1, 100) AS extracted_characters
FROM documents;

This will extract the first 100 characters from the 'text_content' column and display them in the 'extracted_characters' column in the result set.

How to extract a substring containing a specific word using substr in oracle?

To extract a substring containing a specific word using the SUBSTR function in Oracle, you can combine the SUBSTR function with other string functions such as INSTR and LENGTH.

Here is an example:

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SELECT SUBSTR(column_name, 
              INSTR(column_name, 'specific_word') - 1, 
              LENGTH(column_name) - INSTR(column_name, 'specific_word') + 1)
FROM table_name
WHERE INSTR(column_name, 'specific_word') > 0;

In this query:

• Replace column_name with the name of the column in your table that contains the text you want to extract from.
• Replace table_name with the name of your table.
• Replace 'specific_word' with the specific word you want to extract the substring containing it.

This query will extract the substring from column_name that contains the specific word 'specific_word'. The INSTR function is used to find the position of the specific word in the column. The SUBSTR function is then used to extract the substring containing the specific word. The WHERE clause ensures that the specific word is present in the text before extracting the substring.

How to use substr in oracle to extract characters based on a specific condition?

To use the SUBSTR function in Oracle to extract characters based on a specific condition, you can specify the start position and the number of characters to extract. Here is an example of how to use the SUBSTR function with a condition:

Suppose you have a table called "employees" with a column called "full_name" that contains the full name of each employee. You want to extract the first name of employees whose full name contains the string "John".

You can use the SUBSTR function in combination with the INSTR function to achieve this. Here is an example query:

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SELECT SUBSTR(full_name, 1, INSTR(full_name, ' ') - 1) AS first_name
FROM employees
WHERE full_name LIKE '%John%';

In this query:

• The SUBSTR function is used to extract characters from the "full_name" column.
• The second argument specifies the start position as 1 (the beginning of the string).
• The third argument calculates the length of characters to extract based on the position of the first space in the full name (using the INSTR function).
• The WHERE clause filters the results to only include rows where the full name contains the string "John".

This query will return the first name of employees whose full name contains the string "John". You can adjust the condition and substring parameters based on your specific requirements.

What is the behavior of substr when the starting position is greater than the length of the string in oracle?

In Oracle, if the starting position specified in the SUBSTR function is greater than the length of the string, the function will return an empty string (''). It will not throw an error or return null.

How to use substr in oracle to extract characters starting from the end of a string?

In Oracle, you can use the substr function along with negative values to extract characters starting from the end of a string.

Here is an example of how you can use substr to extract the last 3 characters from a string:

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SELECT SUBSTR('Hello World', -3) FROM dual;

This will return 'rld' as it extracts the last 3 characters of the string 'Hello World'.

You can also specify the starting position along with the negative value to extract characters starting from a specific position from the end of the string.

Here is another example of how you can use substr to extract the last 5 characters starting from the 8th position from the end of a string:

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SELECT SUBSTR('Hello World', -8, 5) FROM dual;

This will return 'lo Wor' as it starts extracting characters from the 8th position from the end and extracts a total of 5 characters.

You can adjust the starting position and the number of characters to extract based on your requirements.