Tech Support & Travel

The BITAND function in Oracle is used to perform a bitwise AND operation between two integer values. It returns the bitwise logical AND of the two numbers. 🔹 Syntax: BITAND(number1, number2) number1 , number2 must be integers (or expressions th…

In Oracle, BIN_TO_NUM is a built-in bitwise utility function introduced in Oracle 11g (for bitmap operations). It is used to convert a series of binary flags (0s and 1s) into a single numeric value — basically converting a bit vector into its dec…

Identify Exact Position and Code  in a Column of a table If you want to  see the position and ASCII code  of non-printable characters: SELECT LEVEL AS position, SUBSTR(n2, LEVEL, 1) AS character, ASCII(SUBSTR(n2, LEVEL, 1)) AS ascii_v…

Here is a complete SQL script to create and populate a custom ASCII lookup table with character codes (0–127) and their corresponding descriptions/names . ✅ Step 1: Create the table CREATE TABLE ascii_lookup ( ascii_code NUMBER PRIMARY KEY, …

To create an external table in Oracle that reads from multiple files , you simply list all the files under the LOCATION clause of the ORGANIZATION EXTERNAL clause. ✅ Example: External Table with Multiple Files Assume the files: data1.csv data2.csv…

✅ External Tables in Oracle – Overview & Usage External tables in Oracle allow you to query data in flat files (CSV, pipe-delimited, etc.) as if they are regular database tables , without loading the data into the database. They're read-onl…

Let's troubleshoot and ensure you're using EXCEPTIONS INTO correctly. Here’s a working example step-by-step , tested and compliant with Oracle behavior: ✅ 1. Create a table with duplicate data CREATE TABLE test_emp ( emp_id NUMBER, emp…

When you try to enforce a primary key on an existing table with duplicate values , Oracle will throw an error because primary keys must be unique and non-null . Here’s how you can identify and remove duplicates and then add the primary key constrai…

The ASCII function in Oracle returns the numeric ASCII code of the first character in a string. ✅ Syntax: ASCII(char) char can be a single character or a string — only the first character is considered. The return value is a NUMBER repre…

In Oracle, ADD_MONTHS is a date function used to add or subtract a number of months to a given date. ✅ Syntax ADD_MONTHS(date, number_of_months) date : A valid DATE or TIMESTAMP value. number_of_months : Can be positive (add months) or neg…

In Oracle, a ROWTYPE is a composite data type used in PL/SQL to declare a variable that represents a row of a table or row of a cursor . It allows you to easily manipulate and access an entire row of data without declaring each column individually.…

When a column in an Oracle table stores only two distinct values like 'Yes' or 'No' , creating a standard B-tree index on it is not efficient , because: The column has low cardinality (few distinct values), B-tree indexes are most…