PostgreSQL – How to view the Size of a Table

ByAdmin September 3, 2023September 3, 2023

To get the size of a specific table in PostgreSQL, you can use the pg_total_relation_size function. This function returns the total size of a table in bytes, including the main data file, indexes, and associated objects. Below is the syntax:

SELECT pg_size_pretty(pg_total_relation_size('your_table_name'));

where 'your_table_name' with the name of the table you want to get the size for. When you execute this query, it will return the size of the table in a human-readable format, making it easier to understand.

SELECT pg_size_pretty(pg_total_relation_size('my_table'));

This query will return the size of the “my_table” table in a human-readable format like “123 MB” or “2 GB.”

This query provides an estimate of the total size of the table, including its indexes and related objects. If you want to get more detailed information about the size of individual components (e.g., the table itself, indexes), you can use other PostgreSQL functions and queries like pg_relation_size and pg_indexes_size.

How-To Guides

PostgreSQL – How to List All Installed Extensions

ByAdmin September 4, 2023September 4, 2023

To list all installed extensions in PostgreSQL, you can query the pg_extension system catalog table as shown below: SELECT extname FROM pg_extension; This query retrieves the names of all installed extensions in your PostgreSQL database.

How-To Guides

PostgreSQL – How to List All Columns of A Table

ByAdmin September 7, 2023September 7, 2023

To list all columns of a table in PostgreSQL, you can use the \d command within the psql command-line tool or use SQL queries to retrieve column information from the system catalog. Here are a couple of methods to accomplish this: Method 1: Using psql Open a terminal and start the psql command-line tool by…

How-To Guides

PostgreSQL – How to Add a NOT NULL Constraint

ByAdmin September 8, 2023September 8, 2023

To add a NOT NULL constraint to an existing column in a PostgreSQL table, you can use the ALTER TABLE statement with the ALTER COLUMN clause. Here’s the basic syntax: ALTER TABLE table_name ALTER COLUMN column_name SET NOT NULL; where table_name is the name of the table you want to modify, and column_name is the…

How-To Guides

PostgreSQL – JSON_OBJECT_KEYS Function

ByAdmin September 14, 2023September 14, 2023

You can use the json_object_keys function to extract the keys (field names) from a JSON object in PostgreSQL database. This function takes a JSON object as its argument and returns a set of text values representing the keys in the JSON object. Here is the basic syntax for the json_object_keys function: sqlCopy code json_object_keys(json_object) where…

How-To Guides

PostgreSQL – How to List all Tables

ByAdmin August 31, 2023August 31, 2023

To list all the tables in a PostgreSQL database, you can query the information_schema database which contains metadata about all the tables and other objects in the database. Below is the SQL query you can use to show all the tables: SELECT table_name FROM information_schema.tables WHERE table_schema = ‘public’; This query will retrieve the names…

How-To Guides

PostgreSQL – How to Convert Timestamp to String

ByAdmin September 20, 2023September 20, 2023

You can convert a timestamp to a string in PostgreSQL database using the TO_CHAR function, which allows you to format the timestamp as a string with a specific format. Here’s how you can do it: SELECT TO_CHAR(your_timestamp_column, ‘YYYY-MM-DD HH24:MI:SS’) AS timestamp_string FROM your_table; where The format string ‘YYYY-MM-DD HH24:MI:SS’ specifies the desired format for the…

Related

Similar Posts