Best SQL Books to Buy in October 2025
SQL QuickStart Guide: The Simplified Beginner's Guide to Managing, Analyzing, and Manipulating Data With SQL (Coding & Programming - QuickStart Guides)
Practical SQL, 2nd Edition: A Beginner's Guide to Storytelling with Data
SQL Pocket Guide: A Guide to SQL Usage
SQL Programming QuickStudy Laminated Reference Guide
SQL Queries for Mere Mortals: A Hands-On Guide to Data Manipulation in SQL
Learning SQL: Generate, Manipulate, and Retrieve Data
SQL All-in-One For Dummies (For Dummies (Computer/Tech))
To get the system date and time in Oracle SQL, you can use the SYSDATE function. This function returns the current date and time in the database server's time zone. You can simply call SYSDATE in your SQL query to retrieve the system date and time. Additionally, you can also use the CURRENT_TIMESTAMP function to get the current timestamp, which includes both date and time information. These functions can be useful for various purposes, such as logging the timestamp of data modifications or scheduling tasks based on current date and time.
How to display system time in Oracle SQL?
You can display the system time in Oracle SQL using the SYSDATE function.
Here is an example query that displays the current system time:
SELECT SYSDATE FROM DUAL;
This query will return the current date and time in the default format. You can also format the output using the TO_CHAR function.
For example, to display the system time in a specific format (e.g. 'YYYY-MM-DD HH24:MI:SS'), you can use the following query:
SELECT TO_CHAR(SYSDATE, 'YYYY-MM-DD HH24:MI:SS') AS SYSTEM_TIME FROM DUAL;
This will display the system time in the specified format.
How to get last day of the month in Oracle SQL?
You can get the last day of the month in Oracle SQL by using the LAST_DAY function. Here is an example query to get the last day of the current month:
SELECT LAST_DAY(SYSDATE) AS last_day_of_month FROM DUAL;
This will return the last day of the current month. You can also replace SYSDATE with a specific date to get the last day of a specific month.
How to subtract days from system date in Oracle SQL?
You can subtract days from the system date in Oracle SQL by using the SYSDATE function and the TO_DATE function. Here is an example query that subtracts 5 days from the current system date:
SELECT SYSDATE - 5 FROM dual;
In this query, SYSDATE returns the current system date and time, and subtracting 5 from it will give you the date 5 days ago. The FROM dual is necessary in Oracle SQL to execute a query that does not involve any tables.
You can change the number in the subtraction to subtract a different number of days from the current system date.
How to get the week of the year from a date in Oracle SQL?
To get the week of the year from a date in Oracle SQL, you can use the TO_CHAR function along with the 'IW' format specifier. Here's an example query:
SELECT TO_CHAR(sysdate, 'IW') AS week_of_year FROM dual;
In this query, sysdate is a built-in Oracle function that returns the current date and time. TO_CHAR is used to convert the date into a character data type, and the 'IW' format specifier is used to retrieve the week of the year.
You can replace sysdate with any date column from your table to get the week of the year for that specific date.