![]() ![]() Gives a value to a PostgreSQL variable after declaration.Ĭode: - FUNCTION: public."Initial_val_later"() Illustrate the following SQL statement and snapshot to understand the result of the above function:Ĭode: SELECT public."Initial_val_constant_with_default_keyword"() Public."Initial_val_constant_with_default_keyword"( Public."Initial_val_constant_with_default_keyword"() ![]() SELECT public."Initial_val_constant_without_default_keyword"() Public."Initial_val_constant_without_default_keyword"( Public."Initial_val_constant_without_default_keyword"() DROP FUNCTION public."Initial_val_with_default_keyword"() ĬREATE OR REPLACE FUNCTION public."Initial_val_with_default_keyword"(Ĭode: SELECT public."Initial_val_with_default_keyword"() FUNCTION: public."Initial_val_with_default_keyword"() Illustrate the following SQL statement and snapshot the result of the above function.Ĭode: SELECT public."Initial_val_without_default_keyword"()Ĭode: "Initial_val_with_default_keyword"() DROP FUNCTION public."Initial_val_without_default_keyword"() ĬREATE OR REPLACE FUNCTION public."Initial_val_without_default_keyword"( FUNCTION: public."Initial_val_without_default_keyword"() Without DEFAULT keywordĬonsider the following function of the name:Ĭode: /*"Initial_val_without_default_keyword"()*/ Gives initial value to a PostgreSQL variable. If a PostgreSQL variable is not specified as CONSTANT, we can declare it with a default value and change it later as necessary.We cannot change the variable’s value if any of the PostgreSQL variables is defined as the CONSTANT.We can modify the data stored within the variable.During the execution of the function, we can temporarily store the data in the variable.All of the PostgreSQL variables we use in the function must be defined within the DECLARE keyword.The above example would declare a PostgreSQL variable of name name_of_student having data-type as VARCHAR and having an initial value as ‘John’, which will be changed further as it is specified as CONSTANT. Or DECLARE name_of_student CONSTANT VARCHAR DEFAULT 'John' ![]() DECLARE CONSTANT variableĬonsider the following example to understand the variable declaration with an initial value and as a CONSTANT.Ĭode: DECLARE name_of_student CONSTANT VARCHAR:= 'John' The above example would declare a PostgreSQL variable of name name_of_student having data-type as VARCHAR. DECLARE without initial_valueĬonsider the following example to understand the variable declaration without an initial value. The above example would declare a PostgreSQL variable of name name_of_student having data-type as VARCHAR and initial_value as ‘John’. Or DECLARE name_of_student VARCHAR DEFAULT 'John' DECLARE with initial_valueĬonsider the following example to understand the variable declaration with initial_value.Ĭode: DECLARE name_of_student VARCHAR:= 'John' There are various ways to declare the variable that is given as follows: 1. The above statement would initialize a PostgreSQL variable of name num_of_students with a value of 300. ![]() Now we will initialize the variable by using the following statement: The above example would declare a PostgreSQL variable of name num_of_students having data-type as an integer. We can declare a variable first, and then we can initialize the variable.Ĭonsider the following example to understand the variable initialization after creation. The above example would declare a PostgreSQL variable of name num_of_students having initial_value as 100 and data-type as an integer. Or DECLARE num_of_students integer DEFAULT 100 We can initialize the variable while creating the variable by giving an initial value.Ĭonsider the following example to understand the variable initialization. There are various ways to initialize the variables that are given as follows: 1. How to Initialize Variables in PostgreSQL? If we have not defined the initial_value, then the variable will be assigned with the NULL value. By using this, we can initialize the variable while creating the variable. initial_value: This is an optional component.If we have defined the NOT NULL, then the variable can not have a NULL value. NOT NULL: This is an optional component.data-type: The variable data-type to assign.If we have defined the CONSTANT, we can not change the variable’s value once the variable has been initialized. CONSTANT: This is an optional component.Hadoop, Data Science, Statistics & othersĬonsider the following syntax to declare a variable: DECLARE var_name data-type ![]()
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