如何使用 SQL 从两个数据库中获取数据并插入到临时表中？

Question

I have two databases old and new . I want to count record from both the databases and insert into new temporary table with their table name.

I created temporary table:

CREATE TEMPORARY TABLE tempemp (tablename varchar(50),northwindcount int(11),dest_northwindcount int(11));

and counted records:

select (select count(*) from northwind.orders) as northwind_cnt, (select count(*) from dest_northwind.orders) as dest_northwind_cnt;

How can I insert into temp table?

Answer 1

Dunno about MySql, but in MS SqlServer T-SQL, you'd do something like this:

INSERT INTO
    Tempemp(
       tablename,northwindcount,dest_northwindcount)
SELECT 
    '???' AS table make,
        (SELECT COUNT(*) FROM Northwind.Orders)
       AS Northwindcount,
    (SELECT COUNT(*) FROM Dest_Northwind.Orders) 
        AS dest_northwindcount

My syntax might be a little off, but the general idea is that an INSERT statement can have a SELECT clause instead of a VALUES clause. Maybe something similar in MySql?

Answer 2

i write procedure for this and now this is working. thank you all.

BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE newcount INTEGER;
DECLARE oldcount INTEGER;
DECLARE oldtableName char(50);
DECLARE newtableName char(50);

DECLARE curs1 CURSOR FOR SELECT TABLE_NAME,SUM(TABLE_ROWS) as count FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'dest_northwind' AND 
TABLE_NAME IN(select table_name from information_schema.tables
where table_schema='dest_northwind') GROUP BY TABLE_NAME ;

DECLARE curs2 CURSOR FOR SELECT TABLE_NAME,SUM(TABLE_ROWS) as count FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'northwind' AND 
TABLE_NAME IN(select table_name from information_schema.tables
where table_schema='northwind') GROUP BY TABLE_NAME ;

DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN curs1;
OPEN curs2;
read_loop: LOOP
FETCH curs1 INTO newtableName,newcount;
FETCH curs2 INTO oldtableName,oldcount;
IF done THEN
LEAVE read_loop;
END IF;
SELECT newtableName,newcount,oldcount;
insert into zreult1(Tablename,Northwind,Dest_Northwind)values(oldtableName,oldcount,newcount);
END LOOP;
CLOSE curs1;
CLOSE curs2;
END