In PostgreSQL, variables are often declared within functions or anonymous code blocks. They are used to store temporary data during the execution of a function or script. Variable declaration is primarily achieved through the PL/pgSQL procedural language. This guide explains how to declare variables ...
SELECT column_name INTO variable_name FROM table_name; 复制代码 使用SET语句为变量赋值,然后在后续的SQL语句中直接引用该变量。 SET variable_name = value; 复制代码 在PL/pgSQL中,可以使用DECLARE语句声明变量,并在BEGIN和END之间编写可执行的代码块,直接引用该变量。 DO $$ DECLARE variable_name data_type...
创建表语法:create table table_name ( column_name type column_constraint, table_constraint table_constraint ) inherits existing_table_name; 示例:create table account( user_id serial primary k PostgreSQl建表 主键 外键 表结构 转载 小蝌蚪 2024-03-06 21:54:45 ...
CREATE OR REPLACE FUNCTION f_insert_table( tablename varchar, fieldname text[], fieldvalue text[], out returnValue text ) AS $$ DECLARE ex_result integer default0; ex_sql text; BEGIN ex_sql:='insert into'||quote_ident(tablename)||'('||array_to_string(fieldname,',')||') values('...
declare out_date DATE; out_text varchar2(50); out_num binary_integer; out_boolean boolean; begin ---pl/sql程序的执行部分--- end; 1. 2. 3. 4. 5. 6. 7. 8. 这些变量只可以在该程序块中使用。 1.2%TYPE变量 var_name table.column%type; -- 声明表中某列格式一样的数据类型。 begin...
DECLARE my_variable integer; BEGIN my_variable := 10; END; 复制代码 使用EXECUTE 语句:可以通过 EXECUTE 语句执行一个动态 SQL 语句,并将结果赋给一个变量。例如: EXECUTE 'SELECT column_name FROM table_name WHERE condition' INTO my_variable; 复制代码 这些是在 PostgreSQL 中常用的变量赋值操作方式。
DECLARE std_name TEXT := 'Alex'; std_department VARCHAR(30) := 'Computer Science'; BEGIN std_name='John'; RAISE NOTICE '% is enrolled in % department', std_name, std_department; END $$; In the above code, the initial value of the “std_name” variable is re-initialized in the ...
DECLARE定义一个游标。DECLARE name [ BINARY ] [ INSENSITIVE ] [ [ NO ] SCROLL ] CURSOR [ { WITH | WITHOUT } HOLD ] FOR query [ FOR { READ ONLY | UPDATE [ OF column [, ...] ] } ]DELETE删除一个表中的行。DELETE FROM [ ONLY ] table [ WHERE condition ]...
DECLARE variable_name data_type; 其中,variable_name是变量的名称,data_type是变量的数据类型。 接下来,我们可以使用EXECUTE语句来执行select查询并将结果赋给变量。EXECUTE语句可以执行动态SQL语句,它接受一个字符串参数作为SQL语句,并将结果存储在指定的变量中。例如: EXECUTE 'SELECT column_name FROM t...
eg: 创建一个函数,将查询foo表的一条记录赋给记录变量CREATEFUNCTIONtest_foo_assign_variable()RETURNSRECORDAS$$DECLAREfoo_variable RECORD;BEGINSELECT*INTOfoo_variablefromfoowherefooid=1;RETURNfoo_variable;END; $$LANGUAGEplpgsql; 执行动态命令 当想要在函数中产生动态命令,每次执行涉及到不同表或不同数据类型...