Range partitioning by date in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a partitioned table by date.

PostgreSQL

CREATE TABLE sales (id SERIAL PRIMARY KEY, sale_date DATE, amount NUMERIC) PARTITION BY [1] (sale_date);

Drag options to blanks, or click blank then click option'

AHASH

BLIST

CRANGE

DGROUP

Attempts:

3 left

💡 Hint

Common Mistakes

Using LIST partitioning instead of RANGE for dates.

Using HASH partitioning which is for distributing data evenly.

Range partitioning is used to divide data based on ranges of values, such as dates.

2fill in blank

medium

Complete the code to create a partition for sales in 2023.

PostgreSQL

CREATE TABLE sales_2023 PARTITION OF sales FOR VALUES FROM ('2023-01-01') [1] ('2024-01-01');

Drag options to blanks, or click blank then click option'

ATO

BINCLUSIVE

CEXCLUSIVE

DLESS

Attempts:

3 left

💡 Hint

Common Mistakes

Using EXCLUSIVE which is not valid syntax.

Using LESS which is syntax from other databases like Oracle.

The syntax uses FOR VALUES FROM ... TO ... where TO specifies the exclusive upper bound.

3fill in blank

hard

Fix the error in the partition creation by completing the missing keyword.

PostgreSQL

CREATE TABLE sales_q1_2023 PARTITION OF sales FOR VALUES [1] ('2023-01-01') TO ('2023-04-01');

Drag options to blanks, or click blank then click option'

AON

BIN

CBETWEEN

DFROM

Attempts:

3 left

💡 Hint

Common Mistakes

Using IN which is for list partitions.

Using BETWEEN which is not valid in this syntax.

The correct syntax is FOR VALUES FROM (start) TO (end) for range partitions.

4fill in blank

hard

Fill both blanks to create a partition for sales in the first half of 2024.

PostgreSQL

CREATE TABLE sales_h1_2024 PARTITION OF sales FOR VALUES [1] ('2024-01-01') [2] ('2024-07-01');

Drag options to blanks, or click blank then click option'

AFROM

BIN

CTO

DBETWEEN

Attempts:

3 left

💡 Hint

Common Mistakes

Using IN which is for list partitions.

Using BETWEEN which is not valid syntax here.

Range partitions use FROM and TO to specify the start and end of the range.

5fill in blank

hard

Fill both blanks to create a partition for sales in July 2024.

PostgreSQL

CREATE TABLE sales_july_2024 PARTITION OF sales FOR VALUES [1] ('2024-07-01') [2] ('2024-08-01');

Drag options to blanks, or click blank then click option'

AFROM

BTO

CEXCLUSIVE

DINCLUSIVE

Attempts:

3 left

💡 Hint

Common Mistakes

Using INCLUSIVE which is not valid here.

Omitting the FROM keyword.

The syntax uses FROM and TO to define the range, and TO is exclusive by default.

Practice

1. What is the main purpose of range partitioning by date in PostgreSQL?

easy

A. To create random partitions without any order

B. To split data into parts based on date ranges for better management

C. To encrypt date columns for security

D. To combine all data into a single large table

Solution

1. Step 1: Understand range partitioning concept

   Range partitioning divides data into segments based on continuous ranges, such as dates.

2. Step 2: Identify the purpose of date-based partitioning

   Using date ranges helps organize data by time periods, improving query speed and management.

3. Final Answer:

   To split data into parts based on date ranges for better management -> Option B

4. Quick Check:

   Range partitioning by date = split data by date ranges [OK]

Hint: Range partitioning splits data by continuous date intervals [OK]

Common Mistakes:

• Thinking partitioning combines data instead of splitting
• Confusing partitioning with encryption
• Assuming partitions are random, not range-based

2. Which of the following is the correct syntax to create a range partitioned table by a date column order_date in PostgreSQL?

easy

A. CREATE TABLE orders (id INT, order_date DATE) PARTITION BY RANGE (order_date);

B. CREATE TABLE orders PARTITION BY RANGE (order_date) (id INT, order_date DATE);

C. CREATE TABLE orders (id INT, order_date DATE) PARTITION BY LIST (order_date);

D. CREATE TABLE orders (id INT, order_date DATE) PARTITION BY HASH (order_date);

Solution

1. Step 1: Check correct partitioning clause placement

   In PostgreSQL, PARTITION BY RANGE (column) comes after table columns definition.

2. Step 2: Identify correct partition type for date ranges

   Range partitioning is used for continuous ranges like dates, so PARTITION BY RANGE is correct.

3. Final Answer:

   CREATE TABLE orders (id INT, order_date DATE) PARTITION BY RANGE (order_date); -> Option A

4. Quick Check:

   Syntax: columns then PARTITION BY RANGE [OK]

Hint: Define columns first, then PARTITION BY RANGE (date_column) [OK]

Common Mistakes:

• Placing PARTITION BY before columns
• Using LIST or HASH instead of RANGE for dates
• Incorrect syntax order causing errors

3. Given the following partitioned table and partitions:

CREATE TABLE sales (id INT, sale_date DATE) PARTITION BY RANGE (sale_date);
CREATE TABLE sales_2023 PARTITION OF sales FOR VALUES FROM ('2023-01-01') TO ('2024-01-01');
CREATE TABLE sales_2024 PARTITION OF sales FOR VALUES FROM ('2024-01-01') TO ('2025-01-01');

What will be the result of this query?

SELECT tableoid::regclass, * FROM sales WHERE sale_date = '2023-06-15';

medium

A. Returns rows from sales_2024 partition with sale_date '2023-06-15'

B. Returns no rows because '2023-06-15' is not in any partition

C. Returns rows from both partitions

D. Returns rows from sales_2023 partition with sale_date '2023-06-15'

Solution

1. Step 1: Identify which partition contains '2023-06-15'

   The date '2023-06-15' falls between '2023-01-01' and '2024-01-01', so it belongs to sales_2023 partition.

2. Step 2: Understand query behavior on partitioned tables

   Query on partitioned table routes to matching partition(s) based on WHERE clause; here, only sales_2023 matches.

3. Final Answer:

   Returns rows from sales_2023 partition with sale_date '2023-06-15' -> Option D

4. Quick Check:

   Date in sales_2023 range = rows from sales_2023 [OK]

Hint: Check date range to find correct partition for query [OK]

Common Mistakes:

• Choosing wrong partition based on date
• Assuming query scans all partitions
• Ignoring partition boundaries

4. You try to create a partition for a range partitioned table by date with this command:

CREATE TABLE sales_2025 PARTITION OF sales FOR VALUES FROM ('2025-01-01') TO ('2024-12-31');

What is the problem with this statement?

medium

A. The TO date is earlier than the FROM date, causing a range error

B. Partition names cannot contain numbers

C. You must specify LIST partitioning, not RANGE

D. The sales table must be dropped before adding partitions

Solution

1. Step 1: Check the FROM and TO values in partition definition

   The TO value '2024-12-31' is before the FROM value '2025-01-01', which is invalid for range partitions.

2. Step 2: Understand partition range rules

   Range partitions require FROM value to be less than TO value to define a valid range.

3. Final Answer:

   The TO date is earlier than the FROM date, causing a range error -> Option A

4. Quick Check:

   FROM must be less than TO in range partitions [OK]

Hint: FROM date must be before TO date in range partitions [OK]

Common Mistakes:

• Swapping FROM and TO dates
• Thinking partition names cannot have numbers
• Confusing range with list partitioning

5. You have a large sales table partitioned by month using range partitioning on sale_date. You want to add a new partition for March 2024. Which of the following commands correctly adds this partition?

hard

A. CREATE TABLE sales_2024_03 PARTITION OF sales FOR VALUES FROM ('2024-03-01') TO ('2024-03-31');

B. CREATE TABLE sales_2024_03 PARTITION OF sales FOR VALUES FROM ('2024-02-28') TO ('2024-03-31');

C. CREATE TABLE sales_2024_03 PARTITION OF sales FOR VALUES FROM ('2024-03-01') TO ('2024-04-01');

D. CREATE TABLE sales_2024_03 PARTITION OF sales FOR VALUES FROM ('2024-03-01') TO ('2024-03-30');

Solution

1. Step 1: Understand range partition boundaries for months

   Range partitions use inclusive FROM and exclusive TO, so March 2024 is from '2024-03-01' up to but not including '2024-04-01'.

2. Step 2: Check each option's date range correctness

   CREATE TABLE sales_2024_03 PARTITION OF sales FOR VALUES FROM ('2024-03-01') TO ('2024-04-01'); correctly uses FROM '2024-03-01' TO '2024-04-01'. Options B, C, and D have incorrect boundaries that either overlap or exclude days.

3. Final Answer:

   CREATE TABLE sales_2024_03 PARTITION OF sales FOR VALUES FROM ('2024-03-01') TO ('2024-04-01'); -> Option C

4. Quick Check:

   Range partitions: FROM inclusive, TO exclusive [OK]

Hint: Use TO date as first day of next month for monthly partitions [OK]

Common Mistakes:

• Using TO date as last day of month (should be exclusive)
• Overlapping partition ranges
• Using incorrect FROM dates