ARRAY_POSITIONS function returns the positions of all occurrences of an array element. Here is the basic syntax of using the ARRAY_POSITIONS function. SELECT ARRAY_POSITIONS(array[2,1,3,1,2],1); Above sql returns 2,4 as the output as element ‘1’ occurred in both 2nd and 4th position.
ARRAY_POSITION function in PostgreSQL is used to return the position of the first occurrence of an array element. Here is the basic syntax of using array_position function. SELECT array_position(your_array_column, int)) AS position FROM your_table ; Example of using array_position function: SELECT array_position(array(20, 10, 10, 30), 10) AS position; The output would be 2 ; as…
The array_length function is used to determine the length (number of elements) of a one-dimensional array in PostgreSQL. This function takes two arguments – the array and the dimension for which you want to find the length. Here’s the syntax of the array_length function: array_length(array_expression, dimension) Where: array_expression is the array for which you want…
The unnest function in PostgreSQL is used to transform an array or a set of values into a set of rows. This is particularly useful when you have a column that stores arrays or sets and you want to work with the individual elements within those arrays as separate rows. Below is the basic syntax…
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…
You can convert a string to a date using the TO_DATE function in PostgreSQL. This function allows you to specify the input string, the format of the string, and it will return a date accordingly. The general syntax of the TO_DATE function is as follows: TO_DATE(input_string, format_string) Here’s an example of using SELECT TO_DATE(‘2023-08-31’, ‘YYYY-MM-DD’);…
You can convert a timestamp to a date in PostgreSQL using the DATE function. If you have a timestamp column named “order_ts” in a table called “orders,” you can use the following query to convert the timestamp to a date: SELECT DATE(order_ts) FROM orders; This will return a result set where each row contains the…
Below is the syntax to create a table in PostgreSQL. CREATE TABLE table_name ( column1 datatype1, column2 datatype2, … ); where table_name is the name you want to give to the new table. and column1, column2, etc.: specifies the names of the columns you want to create in the table. and datatype1, datatype2, etc.: specifies…
You can add a unique constraint to a table column using the ALTER TABLE statement. A unique constraint ensures that all values in a column are unique, meaning no two rows can have the same value in that column. Below is the syntax add a unique constraint: ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column_name);…
To create a new user in PostgreSQL, you can use the CREATE USER SQL command. Below is the basic syntax: CREATE USER username [WITH PASSWORD ‘password’]; where username is the desired username for the new user, and [WITH PASSWORD ‘password’] is optional. If you include the password, the user will be created with that password….