CREATE OR REPLACE FUNCTION example_function() RETURNS VOID AS $$ DECLARE my_variable INTEGER := 10; BEGIN RAISE NOTICE 'The value of my_variable is: %', my_variable; END; $$ LANGUAGE plpgsql; 在这个例子中,my_variable 是一个在函数内部声明的整数变量,可以在函数体内部直接引用。 2. 在 ...
Variables in PostgreSQL are declared using the DECLARE keyword within the DO block or CREATE FUNCTION. Here's the basic syntax: DO $$ DECLARE variable_name data_type [DEFAULT value]; BEGIN -- Statements using the variable END $$; Example 1: Declaring and Using a Variable Code: -- Use an...
CREATE OR REPLACE FUNCTION count_db(IN var_b varchar(20)) RETURNS INT8 AS $$ DECLARE v_int INT4; BEGIN SELECT COUNT(*) INTO v_int FROM pg_database WHERE datname like var_b; RETURN v_int; END; $$ LANGUAGE plpgsql; 然后我们从外部来调用这个函数并赋予变量 方法1 失败 [postgres@pg_q...
How to Declare a Variable in Postgres? A variable in Postgres is always declared with a particular data type, such as INTEGER, TEXT, DATE, TIME, etc. Here is the syntax to declare a variable in Postgres: DECLARE var_name < CONSTANT > data_type < NOT NULL > < { DEFAULT | := } ex...
Note that named arguments were added to PL/pgSQL in PostgreSQL 8.0. In earlier versions of PostgreSQL, you must either use the default, numbered variable names for the arguments, or declare aliases in aDECLAREblock: CREATEORREPLACEFUNCTIONfib (integer)RETURNSintegerAS$$DECLAREfib_for ALIASFOR$1;...
/* declaring variable with a default value.*/ helloworld VARCHAR DEFAULT 'PostgreSQL rocks !'; BEGIN RETURN digit; END; $$ LANGUAGE 'plpgsql'; warehouse_db=# create or replace function alias_explain(int) returns integer as $$ declare
DO$$DECLAREmy_variableINTEGER:=42;my_stringTEXT:='Hello, World!';BEGINRAISENOTICE'my_variable: %, my_string: %',my_variable,my_string;END$$; 在此示例中,我们声明了两个变量my_variable和my_string,并分别赋予了整数和字符串值。然后在BEGIN和END之间使用RAISE NOTICE输出变量的值。
(pg_proc);/* Optional anonymous-block handler function */Oid laninlineBKI_DEFAULT(0)BKI_LOOKUP(pg_proc);/* Optional validation function */Oid lanvalidatorBKI_DEFAULT(0)BKI_LOOKUP(pg_proc);#ifdefCATALOG_VARLEN/* variable-length fields start here *//* Access privileges */aclitem lanacl[1]...
] ) CREATE TYPE name ( INPUT = input_function, OUTPUT = output_function [, RECEIVE = receive_function ] [, SEND = send_function ] [, ANALYZE = analyze_function ] [, INTERNALLENGTH = { internal_length | VARIABLE } ] [, PASSEDBYVALUE ] [, ALIGNMENT = alignment ] [, STORAGE = stor...
DECLARE //可选,声明变量 BEGIN EXCEPTION //可选,异常处理 END 存储过程结构是: CREATE OR REPLACE PROCEDURE procedure_name ( para1 IN NUMBER, para2 OUT NUMBER, para3 IN OUT NUMBER ) IS BEGIN ... EXCEPTION ... END procedure_name; 函数的结构是: CREATE OR REPLACE FUNCTION function_name ( ...