How do I assign a variable in PostgreSQL?

How do I assign a variable in PostgreSQL?

PostgreSQL: Declaring Variables

1. Syntax. The syntax to declare a variable in PostgreSQL is: DECLARE variable_name [ CONSTANT ] datatype [ NOT NULL ] [ { DEFAULT | := } initial_value ]
2. Example – Declaring a variable.
3. Example – Declaring a variable with an initial value (not a constant)
4. Example – Declaring a constant.

What is Plpgsql function?

plpgsql is the name of the language that the function is implemented in. Here, we use this option for PostgreSQL, it Can be SQL, C, internal, or the name of a user-defined procedural language. For backward compatibility, the name can be enclosed by single quotes.

How do you declare a variable in a procedure?

Variables in SQL procedures are defined by using the DECLARE statement. Values can be assigned to variables using the SET statement or the SELECT INTO statement or as a default value when the variable is declared. Literals, expressions, the result of a query, and special register values can be assigned to variables.

How do you declare a variable in SQL?

Declaring a variable The DECLARE statement initializes a variable by assigning it a name and a data type. The variable name must start with the @ sign. In this example, the data type of the @model_year variable is SMALLINT . By default, when a variable is declared, its value is set to NULL .

What is plpython3u?

The PostgreSQL language named plpython3u implements PL/Python based on the Python 3 language variant. The language named plpythonu implements PL/Python based on the default Python language variant, which is currently Python 2.

Does redshift use stored procedures?

Stored procedures are commonly used to encapsulate logic for data transformation, data validation, and business-specific logic. By combining multiple SQL steps into a stored procedure, you can reduce round trips between your applications and the database.

Can we write stored procedures in redshift?

You can define an Amazon Redshift stored procedure using the PostgreSQL procedural language PL/pgSQL to perform a set of SQL queries and logical operations. The procedure is stored in the database and is available for any user with sufficient privileges to run.

How to assign a variable in a plpgsql function?

As long as you are assigning a single variable, you can also use plain assignment in a plpgsql function: name := (SELECT t.name from test_table t where t.id = x); Or use SELECT INTOlike @mu already provided. This works, too: name := t.name from test_table t where t.id = x; But better use one of the first two, clearer methods, as @Pavel commented.

How to store query result in a variable in PL / pgSQL?

Learn more Store query result in a variable using in PL/pgSQL Ask Question Asked8 years, 10 months ago Active3 months ago Viewed255k times 148 20 How to assign the result of a query to a variable in PL/pgSQL, the procedural language of PostgreSQL? I have a function:

How is assignment of value to pgSQL variable evaluated?

An assignment of a value to a PL/pgSQL variable is written as: As explained previously, the expression in such a statement is evaluated by means of an SQL SELECT command sent to the main database engine. The expression must yield a single value (possibly a row value, if the variable is a row or record variable).

How is the default value determined in PostgreSQL?

PostgreSQL evaluates the default value of a variable and assigns it to the variable when the block is entered. For example: First, declare a variable whose default value is initialized to the current time. Second, print out the value of the variable and pass the execution in 10 seconds using the pg_sleep () function.