How to declare a variable in a PostgreSQL query. Postgresql Declare Variable. All variables that you will be using within a code block must be declared under the DECLARE keyword. Notice that PL/SQL is case-insensitive, which means v_data and V_DATA refer to the same variable. The system maintains the global variable. A variable holds a value that can be changed through the block or function. In the declaration section, we declared a variable counter and set its value to zero. 773. 0. For example: DECLARE @techonthenet VARCHAR(50); This DECLARE statement example would declare a variable called @techonthenet that is a VARCHAR datatype, with a length of 50 characters.. You then change the value of the @techonthenet variable using the SET statement, as follows: How to declare a variable in a PostgreSQL query . Example - Declare a variable. It can hold only one row of a result set. Please login or register to answer this question. Like dezso commented, do not confuse plpgsql BEGIN (starting a block) with SQL BEGIN; (starting a transaction). The benefit of this is, you do not require to update .sql files for again and again, and multiple people can use same SQL script at a time for different schemas. Variable names in PostgreSQL stored procedures. Syntax: variable_name data_type [:= expression]; Let’s analyze the above syntax: First, specify the name of the variable. Examples: Below is an example of how to declare a variable in PostgreSQL called vSite.. Create functions in PostgreSQL, which are very useful for various features when working with a large amount of data. It is very easy to declare local variables in SQL Server but it seems not possible in PostgreSQL. PostgreSQL: How to change PostgreSQL user password? 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.. vSite: = '';. Conclusion. DECLARE vSite varchar;. 1113. Published: ... it mentions that you can disambiguate column names from variable names by labelling the declaring block: << block >> DECLARE foo int; BEGIN foo: = ... meaning that parameters and special variables can … How to do an update + join in PostgreSQL? ASA ASA. 1 answers to this question. Try to make it as meaningful as possible within 31 characters. How to Declare Variables in PostgreSQL? [ <