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PostgreSQL: How to check if a table exists in a given schema?
There are several ways to check the table exist in the particular schema, some solutions are described below.First, I'll create an "Employee" table and give examples on it. Create the table using the...
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PostgreSQL: Online Test 1
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PostgreSQL: Online Test 2
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PostgreSQL: Online Test 3
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PostgreSQL: Online Test 4
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How to import CSV file data into a PostgreSQL table?
My first task was to import CSV data to PostgreSQL after finishing the schema/table design. It was very challenging for me because I was new on PostgreSQL, but I was familiar with SQL Server. I...
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How to select the nth row of the table in PostgreSQL?
Here we will discuss the technique to fetch nth row of the table in PostgreSQL. I will use the concept of the LIMIT and OFFSET Clause.Syntax to fetch nth row of the table in PostgreSQL SELECT col_1,...
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MongoDB Online Test 1
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MongoDB Online Test 2
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MongoDB Online Test 3
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MongoDB Online Test 4
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MongoDB Online Test 5
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NUnit : Introduction
There are several unit test tools in the market, but one of them is NUnit, the most popular tool for doing unit testing. So in this tutorial, we will learn the Unit Testing using the NUnit tool and...
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How to List columns with indexes in PostgreSQL?
Problem: I have a table of the customer below, and I want to list column with indexes in PostgreSQL, Basically purpose of this question is an analysis of the performance. CREATETABLECustomer(...
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Fatal Error: Peer authentication failed for user "postgres", when trying to...
Problem: Sometimes, we get the following error when trying to make a connection in Rails. FATAL ERROR: Peer authentication failed for user "postgres" Solution: There are a lot of solutions described...
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PostgreSQL: Stored Procedure
The stored procedure is introduced in PostgreSQL 11 that supports the transaction. Postgres user-defined function has a drawback, it can not execute transactions. It means, in the function, we can not...
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PostgreSQL: Generated Column
PostgreSQL 12 introduced a new feature called generated columns. Other popular databases already support to generated columns as the Computed column and virtual column.What is a generated column?A...
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How to concatenate the string values of a column/field in a PostgreSQL query?
This is a very popular interview question of the database, many times I faced this the question in SQL Server interview. Problem:Suppose we have the following table...
View ArticlePostgreSQL: How to create a read only user?
Suppose you are Super Admin, sometimes you need to give the read-only permission to particular user for a safety purpose, because, it may be possible a specific user don’t have sufficient knowledge...
View ArticlePostgreSQL: how to select all records from one table that do not exist in...
Problem: I have two tables one is Employee, and another is Address, and I want to fetch all those records from Employee, which doesn't exist in the Address table.--EmployeeCREATETABLEemployee(...
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