CURRENT_DATE and CURRENT_TIMESTAMP in SQL - Step-by-Step Execution

Concept Flow - CURRENT_DATE and CURRENT_TIMESTAMP

Start Query

↓

Evaluate CURRENT_DATE

↓

Return current date only

↓

Evaluate CURRENT_TIMESTAMP

↓

Return current date and time

↓

Display results

↓

End Query

The query first gets the current date, then the current date and time, and finally shows both results.

Execution Sample

SQL

SELECT CURRENT_DATE AS today, CURRENT_TIMESTAMP AS now;

This query returns the current date and the current date with time.

Execution Table

Step	Action	Evaluation	Result
1	Start query execution	N/A	Query begins
2	Evaluate CURRENT_DATE	Gets current date only	2024-06-15
3	Evaluate CURRENT_TIMESTAMP	Gets current date and time	2024-06-15 14:23:45
4	Return results	Show both values in output	today=2024-06-15, now=2024-06-15 14:23:45
5	End query	All values returned	Query complete

💡 Query ends after returning current date and timestamp values

Variable Tracker

Variable	Start	After Evaluation	Final
today	NULL	2024-06-15	2024-06-15
now	NULL	2024-06-15 14:23:45	2024-06-15 14:23:45

Key Moments - 2 Insights

Why does CURRENT_DATE return only the date without time?

CURRENT_DATE is designed to return only the date part, as shown in execution_table step 2, so the time is not included.

Why does CURRENT_TIMESTAMP include both date and time?

CURRENT_TIMESTAMP returns the full date and time, as seen in execution_table step 3, because it captures the exact moment the query runs.

Visual Quiz - 3 Questions

Look at the execution_table, what value does 'today' have after evaluation?

A 2024-06-15

B 2024-06-15 14:23:45

C NULL

D 2024-01-01

💡 Hint

Check the 'today' variable value in variable_tracker after evaluation

At which step does the query get the current date and time?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Look at execution_table step descriptions for CURRENT_TIMESTAMP evaluation

If you only want the date without time, which function should you use?

A CURRENT_TIMESTAMP

B NOW()

C CURRENT_DATE

D GETDATE()

💡 Hint

Refer to key_moments about which function returns date only

Concept Snapshot

CURRENT_DATE returns the current date only (YYYY-MM-DD).
CURRENT_TIMESTAMP returns current date and time (YYYY-MM-DD HH:MM:SS).
Use CURRENT_DATE when time is not needed.
Use CURRENT_TIMESTAMP to get exact current time.
Both are evaluated at query run time.

Full Transcript

This visual execution trace shows how SQL functions CURRENT_DATE and CURRENT_TIMESTAMP work. The query starts and first evaluates CURRENT_DATE, which returns only the date part like 2024-06-15. Then it evaluates CURRENT_TIMESTAMP, which returns the full date and time like 2024-06-15 14:23:45. Both values are returned as query output. The variable tracker shows how 'today' and 'now' variables get their values step by step. Key moments clarify that CURRENT_DATE excludes time, while CURRENT_TIMESTAMP includes it. The quiz questions help reinforce understanding by asking about values at specific steps and correct function usage. This helps beginners see exactly how these functions behave during query execution.

Practice

1. What does the SQL function CURRENT_DATE return?

easy

A. The current date without the time part

B. The current time without the date part

C. The current date and time together

D. The date and time of the last database update

Solution

1. Step 1: Understand the function purpose

   CURRENT_DATE is designed to return only the date part of the current moment.

2. Step 2: Compare with other functions

   CURRENT_TIMESTAMP returns date and time, but CURRENT_DATE excludes time.

3. Final Answer:

   The current date without the time part -> Option A

4. Quick Check:

   CURRENT_DATE = date only [OK]

Hint: CURRENT_DATE returns only date, no time included [OK]

Common Mistakes:

• Confusing CURRENT_DATE with CURRENT_TIMESTAMP
• Expecting time part in CURRENT_DATE
• Thinking CURRENT_DATE returns last update time

2. Which of the following is the correct syntax to get the current date and time in SQL?

easy

A. SELECT CURRENT_DATE();

B. SELECT CURRENT_TIMESTAMP;

C. SELECT NOW();

D. SELECT CURRENT_TIME;

Solution

1. Step 1: Identify correct function syntax

   CURRENT_TIMESTAMP is a standard SQL function and does not require parentheses.

2. Step 2: Check other options

   CURRENT_DATE() is invalid syntax because CURRENT_DATE does not use parentheses; NOW() is valid in some databases but not standard SQL; CURRENT_TIME returns only time.

3. Final Answer:

   SELECT CURRENT_TIMESTAMP; -> Option B

4. Quick Check:

   CURRENT_TIMESTAMP syntax correct without parentheses [OK]

Hint: CURRENT_TIMESTAMP has no parentheses in standard SQL [OK]

Common Mistakes:

• Adding parentheses to CURRENT_DATE or CURRENT_TIMESTAMP
• Using NOW() assuming it's standard SQL
• Confusing CURRENT_TIME with date and time

3. Given the SQL query:

SELECT CURRENT_DATE, CURRENT_TIMESTAMP FROM dual;

What will be the output format of CURRENT_TIMESTAMP?

medium

A. Only the date in YYYY-MM-DD format

B. A Unix timestamp number

C. Only the time in HH:MM:SS format

D. Date and time in YYYY-MM-DD HH:MM:SS format

Solution

1. Step 1: Understand CURRENT_TIMESTAMP output

   CURRENT_TIMESTAMP returns both date and time, typically in the format YYYY-MM-DD HH:MM:SS.

2. Step 2: Compare with other options

   CURRENT_DATE returns only date; time-only or Unix timestamp are not returned by CURRENT_TIMESTAMP.

3. Final Answer:

   Date and time in YYYY-MM-DD HH:MM:SS format -> Option D

4. Quick Check:

   CURRENT_TIMESTAMP = date + time [OK]

Hint: CURRENT_TIMESTAMP always includes date and time [OK]

Common Mistakes:

• Expecting only date from CURRENT_TIMESTAMP
• Thinking CURRENT_TIMESTAMP returns Unix timestamp
• Confusing CURRENT_TIMESTAMP with CURRENT_TIME

4. You wrote this SQL query:

SELECT CURRENT_DATE(), CURRENT_TIMESTAMP() FROM users;

But it gives an error. What is the problem?

medium

A. CURRENT_DATE and CURRENT_TIMESTAMP should not have parentheses

B. The table name 'users' is missing quotes

C. CURRENT_DATE and CURRENT_TIMESTAMP are not valid SQL functions

D. You must use NOW() instead of CURRENT_TIMESTAMP

Solution

1. Step 1: Check function syntax

   In standard SQL, CURRENT_DATE and CURRENT_TIMESTAMP are special functions without parentheses.

2. Step 2: Validate other parts

   The table name 'users' does not require quotes; both functions are valid; NOW() is optional but not required.

3. Final Answer:

   CURRENT_DATE and CURRENT_TIMESTAMP should not have parentheses -> Option A

4. Quick Check:

   No parentheses with CURRENT_DATE/TIMESTAMP [OK]

Hint: Remove parentheses from CURRENT_DATE and CURRENT_TIMESTAMP [OK]

Common Mistakes:

• Adding parentheses to CURRENT_DATE or CURRENT_TIMESTAMP
• Thinking table names need quotes
• Replacing CURRENT_TIMESTAMP with NOW() unnecessarily

5. You want to insert a new record into a table events with a column created_at that stores the exact date and time of insertion. Which SQL statement correctly uses CURRENT_TIMESTAMP for this purpose?

hard

A. INSERT INTO events (name, created_at) VALUES ('Launch', CURRENT_DATE);

B. INSERT INTO events (name, created_at) VALUES ('Launch', CURRENT_TIME);

C. INSERT INTO events (name, created_at) VALUES ('Launch', CURRENT_TIMESTAMP);

D. INSERT INTO events (name, created_at) VALUES ('Launch', NOW());

Solution

1. Step 1: Identify correct timestamp function

   CURRENT_TIMESTAMP returns the full date and time, perfect for recording insertion time.

2. Step 2: Compare other options

   CURRENT_DATE lacks time; NOW() may work but is not standard SQL; CURRENT_TIME returns only time, missing date.

3. Final Answer:

   INSERT INTO events (name, created_at) VALUES ('Launch', CURRENT_TIMESTAMP); -> Option C

4. Quick Check:

   Use CURRENT_TIMESTAMP for full date and time [OK]

Hint: Use CURRENT_TIMESTAMP to store date and time on insert [OK]

Common Mistakes:

• Using CURRENT_DATE instead of CURRENT_TIMESTAMP
• Using CURRENT_TIME missing the date part
• Assuming NOW() is always standard SQL