WHERE tablename = 'table_one' ) THEN ( SELECT 'success' :: void)ĮLSE ( SELECT create_user_specific_table()) SELECT CASE WHEN ( SELECT true :: BOOLEAN FROM pg_catalog. Use a CASE Statement to Create a Table if It Does Not Exist in PostgreSQLĬREATE OR REPLACE FUNCTION create_user_specific_table()ĬREATE TABLE table_one (u_name varchar(50) not null You can also modify this function as it fits better to your needs. The RAISE NOTICE function is what implements this functionality.ĭifferent implementations of this function can be used to CREATE a table in PostgreSQL. Instead, it will raise a notice that The table already exists. Inside the function, if the table is already present inside the listed tables, it won’t be created. The $func$ is the start and end tag of the function. It can be used effectively for testing, rather than deleting the function listed and then creating it again. Hence, you won’t run into an error while calling the function again and again. You’ll see the CREATE or REPLACE written behind the function defined.ĬREATE or REPLACE tends to replace the existing function definition given inside the system if it has already been integrated inside the database. Now, let’s try to analyze how this works. INSERT INTO table_one (u_name) values( 'Jonathon') RAISE NOTICE 'Table table_one already exists.' ĬREATE TABLE table_one (u_name varchar(50)) IF EXISTS (SELECT FROM pg_catalog.pg_tables One of the most straightforward queries to perform this operation is writing out a standard SQL CREATE TABLE, as shown below.ĬREATE or replace FUNCTION create_user_specific_table() Use the CREATE TABLE Query to Create a Table if It Does Not Exist in PostgreSQL PostgreSQL is an object-relational database system which means that it can support much more complex data types than its contender, MySQL.Īside from the difference mentioned, PostgreSQL tends to be very similar in structure when writing queries with MySQL or any other database system.īecause the backbone of each is RDBMS, all SQL queries are pretty much the same in both instances, with just extensions for each system that they may create individually.Ĭreating a table in PostgreSQL is very easy, and in this article, we will discuss all the ways we can write out queries that help us in table creation. Use a CASE Statement to Create a Table if It Does Not Exist in PostgreSQL.Use the CREATE or REPLACE Query to Create a Table if It Does Not Exist in PostgreSQL.Use the CREATE TABLE Query to Create a Table if It Does Not Exist in PostgreSQL.
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