Kepiye MySQL nggawe / nyelehake tabel sementara? Peran tabel sementara MySQL

MySQLKepiye carane nggawe / nyelehake tabel suhu?MySQLPeran tabel sementara

Tabel sementara MySQL

Tabel sementara MySQL migunani banget nalika kita kudu nyimpen sawetara data sementara.Tabel sauntara mung katon ing sambungan saiki. Nalika sambungan ditutup, Mysql bakal kanthi otomatis mbusak tabel lan ngeculake kabeh spasi.

Tabel sementara ditambahake ing MySQL versi 3.23. Yen versi MySQL luwih murah tinimbang versi 3.23, sampeyan ora bisa nggunakake tabel sementara MySQL.Nanging, saiki wis jarang nggunakake versi sing kurang.database MySQLlayanan.

Tabel sauntara MySQL mung katon ing sambungan saiki.Yen sampeyan nggunakake skrip PHP kanggo nggawe tabel sauntara MySQL, tabel sauntara bakal dirusak kanthi otomatis saben skrip PHP dieksekusi.

Yen sampeyan nggunakake program klien MySQL liyane kanggo nyambung menyang server database MySQL kanggo nggawe tabel sementara, tabel sauntara mung bakal dirusak nalika program klien ditutup.

Kadadeyan

Ing ngisor iki nuduhake conto prasaja nggunakake tabel sauntara MySQL, kode SQL ing ngisor iki bisa ditrapake kanggo fungsi mysql_query () saka script PHP.

MySQL的> CREATE TEMPORARY TABLE SalesSummary （- > PRODUCT_NAME VARCHAR （50 ）NOT NULL
     - > ，TOTAL_SALES DECIMAL （12 ，2 ）NOT NULL DEFAULT 0.00 - > ，avg_unit_price DECIMAL （7 ，2 ）NOT NULL DEFAULT 0.00 - > ，total_units_sold INT UNSIGNED NOT NULL DEFAULT 0 ）; 查询OK ，0 行受影响（0.00 秒 
     
     
     

 ）

的MySQL > INSERT INTO SalesSummary - > （PRODUCT_NAME ，TOTAL_SALES ，avg_unit_price ，total_units_sold ）- > VALUES
     - > （'黄瓜' ，100.25 ，90 ，2 ）;
     
        

mysql > SELECT * FROM SalesSummary ; + -------------- + ------------- + ---------------- + --- --------------- + | product_name | total_sales | avg_unit_price | total_units_sold | + -------------- + ------------- + ---------------- + --- --------------- + | 黄瓜      | 100.25 | 90.00 | 2 | + -------------- + ------------- + ---------------- + --- --------------- + 1 行中集合（0.00 秒）



                                   

  

nalika sampeyan nggunakakeTampilake tabelNalika printah nampilake dhaptar tabel data, sampeyan ora bakal bisa ndeleng tabel SalesSummary.

Yen sampeyan metu saka sesi MySQL saiki, banjur gunakakePilihprintah kanggo maca data tabel sak wentoro Originally digawe, banjur sampeyan bakal nemokake sing tabel ora ana ing database, amarga tabel sak wentoro wis numpes nalika metu.

Selehake tabel sementara MySQL

Kanthi gawan, tabel sauntara otomatis numpes nalika sampeyan medhot saka database.Mesthi sampeyan uga bisa nggunakake ing sesi MySQL saikiDROP TABELprintah kanggo nyelehake tabel sauntara kanthi manual.

Ing ngisor iki minangka conto ngeculake tabel sementara kanthi manual:

mysql> CREATE TEMPORARY TABLE SalesSummary (
    -> product_name VARCHAR(50) NOT NULL
    -> , total_sales DECIMAL(12,2) NOT NULL DEFAULT 0.00
    -> , avg_unit_price DECIMAL(7,2) NOT NULL DEFAULT 0.00
    -> , total_units_sold INT UNSIGNED NOT NULL DEFAULT 0
);
Query OK, 0 rows affected (0.00 sec)

mysql> INSERT INTO SalesSummary
    -> (product_name, total_sales, avg_unit_price, total_units_sold)
    -> VALUES
    -> ('cucumber', 100.25, 90, 2);

mysql> SELECT * FROM SalesSummary;
+--------------+-------------+----------------+------------------+
| product_name | total_sales | avg_unit_price | total_units_sold |
+--------------+-------------+----------------+------------------+
| cucumber     |      100.25 |          90.00 |                2 |
+--------------+-------------+----------------+------------------+
1 row in set (0.00 sec)
mysql>DROP TABLE SalesSummary ; 
mysql >   SELECT * FROM SalesSummary ; 
错误1146 ：表'chenweiliang.SalesSummary' 不存在