Contents
How can I get list of column names in PostgreSQL using query?
How can I get a list of column names and datatypes of a table in PostgreSQL using a query?
How is the count ( ) function used in PostgreSQL?
The COUNT () function is an aggregate function that allows you to get the number of rows that match a specific condition of a query. The following statement illustrates various ways of using the COUNT () function.
How to find number of columns in a database?
Query returns basic statistics of numbers of columns in a database. There are no comments. Click here to write the first comment.
How to calculate the number of payments in PostgreSQL?
PostgreSQL COUNT() with GROUP BY clause To get the number of payments by the customer, you use the GROUP BY clause to group the payments into groups based on customer id, and use the COUNT() function to count the payments for each group.
How to rename a column in a PostgreSQL table?
CREATE VIEW customer_data AS SELECT c.id, c.name, g.name customer_group FROM customers c INNER JOIN customer_groups g ON g.id = c.group_id; The following statement uses the ALTER TABLE RENAME COLUMN statement to rename the email column of the customers table to contact_email:
When to use a leading double colon in SQL Server?
In MS SQL Server 2000: For built-in user-defined functions that return a table, the function name must be specified with a leading double colon (::) to distinguish it from user-defined functions that are not built-in. It also must be specified as a one-part name with no database or owner qualifications.
Is the column keyword optional in PostgreSQL?
The COLUMN keyword in the statement is optional therefore you can omit it like this: For some reason, if you try to rename a column that does not exist, PostgreSQL will issue an error. Unfortunately that PostgreSQL does not provide the IF EXISTS option for the RENAME clause.
https://www.youtube.com/watch?v=B9eEnjSiUAw