16

このようなコードがあります。テーブルには、保持する必要のある自動インクリメントフィールドもあります（他のテーブルで使用されます）。このコードを単純化して最適化したいと思います。

$query ="SELECT * FROM models WHERE col1 = 'foo'";
$testResult = mysql_query($query) or die('Error, query failed');    

if(mysql_fetch_array($testResult) == NULL){
    //insert...
    $query ="INSERT INTO models (col1, col2, col3)
    VALUES ('foo', 'bar', 'alph')";
    $result = mysql_query($query) or die('Error, query failed');
}else{
    //update...
    $query = "UPDATE models
        SET col1='foo', col2='bar', col3='alph'
        WHERE col1='foo' AND col2='bar'";
        $result = mysql_query($query) or die('Error, query failed');        
}

編集：主キーIDは、自動インクリメントされるフィールドです。私はこれを変えたくありません。ただし、別のフィールドが重複している場合は、そのレコードを更新する必要があります。

4

4 に答える 4

28

REPLACE INTOはどうですか？

REPLACE INTO models
( col1, col2, col3 )
VALUES
( 'foo', 'bar', 'alpha' )

col1が主キーであるとすると、値が「foo」の行がすでに存在する場合、他の2つの列が更新されます。それ以外の場合は、新しい行が挿入されます。

于 2012-04-10T20:13:34.410 に答える
7

重複する場合にのみcol3を更新する必要があります。これはまさにあなたが求めているものです。

INSERT INTO models (col1, col2, col3)
VALUES ('foo', 'bar', 'alpha')
ON DUPLICATE KEY UPDATE col3='alpha';
于 2012-04-10T20:15:18.690 に答える
7

「INSERT...ONDUPLICATEKEYUPDATE」構文を使用してみてください

http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

If you specify ON DUPLICATE KEY UPDATE, and a row is inserted that would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row is performed. For example, if column a is declared as UNIQUE and contains the value 1, the following two statements have identical effect:

INSERT INTO table (a,b,c) VALUES (1,2,3)
  ON DUPLICATE KEY UPDATE c=c+1;

UPDATE table SET c=c+1 WHERE a=1;
The ON DUPLICATE KEY UPDATE clause can contain multiple column assignments, separated by commas.

With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if the row is inserted as a new row and 2 if an existing row is updated.

If column b is also unique, the INSERT is equivalent to this UPDATE statement instead:

UPDATE table SET c=c+1 WHERE a=1 OR b=2 LIMIT 1;
If a=1 OR b=2 matches several rows, only one row is updated. In general, you should try to avoid using an ON DUPLICATE KEY clause on tables with multiple unique indexes.

You can use the VALUES(col_name) function in the UPDATE clause to refer to column values from the INSERT portion of the INSERT ... UPDATE statement. In other words, VALUES(col_name) in the UPDATE clause refers to the value of col_name that would be inserted, had no duplicate-key conflict occurred. This function is especially useful in multiple-row inserts. The VALUES() function is meaningful only in INSERT ... UPDATE statements and returns NULL otherwise. Example:

INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6)
  ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);
That statement is identical to the following two statements:

INSERT INTO table (a,b,c) VALUES (1,2,3)
  ON DUPLICATE KEY UPDATE c=3;
INSERT INTO table (a,b,c) VALUES (4,5,6)
  ON DUPLICATE KEY UPDATE c=9;
If a table contains an AUTO_INCREMENT column and INSERT ... UPDATE inserts a row, the LAST_INSERT_ID() function returns the AUTO_INCREMENT value. If the statement updates a row instead, LAST_INSERT_ID() is not meaningful. However, you can work around this by using LAST_INSERT_ID(expr). Suppose that id is the AUTO_INCREMENT column. To make LAST_INSERT_ID() meaningful for updates, insert rows as follows:

INSERT INTO table (a,b,c) VALUES (1,2,3)
  ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id), c=3;
The DELAYED option is ignored when you use ON DUPLICATE KEY UPDATE.
于 2012-04-10T20:08:53.630 に答える
3

MySQL 5.0 +の場合：INSERT ON DUPLICATE KEY UPDATE

http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

于 2012-04-10T20:10:18.163 に答える