('a', 1); insert into users values ('b', 2); insert into users values ('b', 3); CREATE OR REPLACE FUNCTION get_userid(name text) RETURNS int AS $$ #print_strict_params on DECLARE userid int; username text; BEGIN SELECT userid, username INTO userid, username FROM users WHERE ...
CREATE OR REPLACE FUNCTION count_db(IN var_b varchar(20)) RETURNS INT8 AS $$ DECLARE v_int INT4; BEGIN SELECT COUNT(*) INTO v_int FROM pg_database WHERE datname like var_b; RETURN v_int; END; $$ LANGUAGE plpgsql; 然后我们从外部来调用这个函数并赋予变量 方法1 失败 [postgres@pg_q...
DO $$ DECLARE variable_name data_type; BEGIN variable_name := value; -- 在此处编写使用变量的代码 END $$; 复制代码 在函数或存储过程中,可以声明变量并在函数或存储过程中使用该变量。 CREATE OR REPLACE FUNCTION function_name() RETURNS void AS $$ DECLARE variable_name data_type; BEGIN variable_...
v_rec tbl_employee_info%ROWTYPE; 三、PL/SQL程序中的SELECT/UPDATE/INSERT/DELETE SQL语法和隐式游标 使用SELECT INTO语法从数据库中提取一行记录: SELECT select_list INTO variable_name | record_name FROM table WHERE condition; 这个语句可能会抛出NO_DATA_FOUND或TOO_MANY_ROWS异常。 UPDATE/INSERT/DELETE...
< function_body > [...] RETURN { variable_name | value } END; LANGUAGE plpgsql; 很容易理解,不多解释 下面我对一张表进行简单操作,逐步递进的介绍存储过程的语法 步骤1-基础版 into 表示把结果赋值给 后面的变量,该变量必须在 declare 提前声明 ...
custom_variable_classes = 'auto_explain' auto_explain.log_min_duration = 4s 51.数据库备份 select pg_start_backup('backup baseline'); select pg_stop_backup(); recovery.conf restore_command='cp /opt/buxlog/%f %p' 52.重建索引 REINDEX { INDEX | TABLE | DATABASE | SYSTEM } name [ FORCE...
] ) 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...
INPUT = input_function, OUTPUT = output_function [, RECEIVE = receive_function ] [, SEND = send_function ] [, ANALYZE = analyze_function ] [, INTERNALLENGTH = { internal_length | VARIABLE } ] [, PASSEDBYVALUE ] [, ALIGNMENT = alignment ] ...
CREATE OR REPLACE FUNCTION pv ( future_value NUMBER , periods NUMBER , interest NUMBER ) RETURN NUMBER DETERMINISTIC IS BEGIN RETURN future_value/((1+interest)**periods); END pv; --SQL Command->编译->执行: var res NUMBER call pv(10000,5,6) into :res; ...
Group By – divide rows of a result set into groups and optionally apply an aggregate function to each group. Having – apply conditions to groups, which allow you to filter groups. Section 5. Set Operations Union – combine result sets of multiple queries into a single result set. ...