Assignment Statements

Variable Syntax

Figure 1 shows the syntax diagram for assigning a value to a variable.

Figure 1 assignment_value::=

The above syntax diagram is explained as follows:

• variable_name: specifies the name of a variable.
• value can be a value or an expression. The type of value must be compatible with the type of variable_name.

Variable Value Assignment Example

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openGauss=# DECLARE
    emp_id  INTEGER := 7788; -- Assignment
BEGIN
    emp_id := 5; -- Assignment
    emp_id := 5*7784;
END;
/

INTO/BULK COLLECT INTO

INTO and BULK COLLECT INTO store values returned by statements in a stored procedure to variables. BULK COLLECT INTO allows some or all returned values to be temporarily stored in an array.

Example

openGauss=# DROP TABLE IF EXISTS customers;
openGauss=# CREATE TABLE customers(id int,name varchar);
openGauss=# INSERT INTO customers VALUES(1,'ab');
openGauss=# DECLARE
    my_id integer;
BEGIN
    select id into my_id from customers limit 1; -- Assign a value.
END;
/

openGauss=# DECLARE
    type id_list is varray(6) of customers.id%type;
    id_arr id_list;
BEGIN
    select id bulk collect into id_arr from customers order by id DESC limit 20; -- Assign values in batches.
END;
/

BULK COLLECT INTO can only assign values to arrays or collections in batches. Use LIMIT properly to prevent performance deterioration caused by excessive operations on data.