To get the name of the current database in PostgreSQL, you can use the following SQL query:
SELECT current_database();When you execute this query, it will return the name of the database that you are currently connected to.
For example, if you are connected to a database named “my_database,” executing the query will return “my_database” as the result.
To get the first day of the month from a date in PostgreSQL, you can use the DATE_TRUNC function. Here’s an example: SELECT DATE_TRUNC(‘month’, your_date_column) AS first_day_of_month FROM your_table; where your_date_column is the name of your date column and your_table is the name of your table. This query will return the first day of the…
To delete duplicate rows in PostgreSQL using a self-join, you can use the DELETE statement along with a self-join condition. Here’s the syntax: DELETE FROM your_table a USING your_table b WHERE a.column_name = b.column_name AND a.ctid < b.ctid; where your_table is the actual name of your table, and column_name is the column that you want…
To rename a column in PostgreSQL, you can use the ALTER TABLE statement with the RENAME COLUMN clause. Below is the basic syntax for renaming a column in PostgreSQL: ALTER TABLE table_name RENAME COLUMN old_column_name TO new_column_name; where table_name is the name of the table containing the column you want to rename, old_column_name is the…
To list views in a PostgreSQL database, you can use SQL queries to query the system catalog tables. Specifically, you can query the pg_views catalog table to retrieve information about the views in the database. Here’s how you can do it: SELECT table_name FROM information_schema.views WHERE table_schema = ‘public’; where This query will return a…
To update multiple columns in a PostgreSQL table, you can use the UPDATE statement. Below is the basic syntax for updating multiple columns: UPDATE table_name SET column1 = value1, column2 = value2, … WHERE condition; where Here’s an example of how to update multiple columns in a PostgreSQL table: Suppose you have a table named…
Creating a materialized view in PostgreSQL involves using the CREATE MATERIALIZED VIEW statement. A materialized view is a precomputed and stored view of the data from one or more tables. Using materialized views can improve query performance by reducing the need to repeatedly compute the same complex queries. Here’s the basic syntax for creating a…