mysql update column with value from another table

I have two tables, both looking like

id  name  value
===================
1   Joe     22
2   Derk    30

I need to copy the value of value from tableA to tableB based on check name in each table.

Any tips for this UPDATE statement?

In addition to this answer if you need to change tableB.value according to tableA.value dynamically you can do for example:

UPDATE tableB
INNER JOIN tableA ON tableB.name = tableA.name
SET tableB.value = IF(tableA.value > 0, tableA.value, tableB.value)
WHERE tableA.name = 'Joe'

you need to join the two tables:

for instance you want to copy the value of name from tableA into tableB where they have the same ID

UPDATE tableB t1 
        INNER JOIN tableA t2 
             ON t1.id = t2.id
SET t1.name = t2.name 
WHERE t2.name = 'Joe'

UPDATE 1

UPDATE tableB t1 
        INNER JOIN tableA t2 
             ON t1.id = t2.id
SET t1.name = t2.name 

UPDATE 2

UPDATE tableB t1 
        INNER JOIN tableA t2 
             ON t1.name = t2.name
SET t1.value = t2.value

Second possibility is,

UPDATE TableB 
SET TableB.value = (
    SELECT TableA.value 
    FROM TableA
    WHERE TableA.name = TableB.name
);

    UPDATE    cities c,
          city_langs cl
    SET       c.fakename = cl.name
   WHERE     c.id = cl.city_id

The second option is feasible also if you're using safe updates mode (and you're getting an error indicating that you've tried to update a table without a WHERE that uses a KEY column), by adding:

UPDATE TableB  
SET TableB.value = (  
SELECT TableA.value  
    FROM TableA  
    WHERE TableA.name = TableB.name  
)  
**where TableB.id < X**  
;

Store your data in temp table

Select * into tempTable from table1

Now update the column

 UPDATE table1
 	SET table1.FileName = (select FileName from tempTable where tempTable.id = table1.ID);

In my case, the accepted solution was just too slow. For a table with 180K rows the rate of updates was about 10 rows per second. This is with the indexes on the join elements.

I finally resolved my issue using a procedure:

CREATE DEFINER=`my_procedure`@`%` PROCEDURE `rescue`()
BEGIN
	declare str VARCHAR(255) default '';
	DECLARE n INT DEFAULT 0;
	DECLARE i INT DEFAULT 0;
	DECLARE cur_name VARCHAR(45) DEFAULT '';
	DECLARE cur_value VARCHAR(10000) DEFAULT '';
	SELECT COUNT(*) FROM tableA INTO n;
	SET i=0;
	WHILE i<n DO 
	  SELECT namea,valuea FROM tableA limit i,1 INTO cur_name,cur_value;
	  UPDATE tableB SET nameb=cur_name where valueb=cur_value;
	  SET i = i + 1;
	END WHILE;

END

I hope it will help someone in the future like it helped me

If you have common field in both table then it's so easy !....

Table-1 = table where you want to update. Table-2 = table where you from take data.

1. make query in Table-1 and find common field value.
2. make a loop and find all data from Table-2 according to table 1 value.
3. again make update query in table 1.

$qry_asseet_list = mysql_query("SELECT 'primary key field' FROM `table-1`");
  
$resultArray = array();
while ($row = mysql_fetch_array($qry_asseet_list)) {
$resultArray[] = $row;
}



foreach($resultArray as $rec) {
	
	$a = $rec['primary key field'];

	$cuttable_qry = mysql_query("SELECT * FROM `Table-2` WHERE `key field name` = $a");

	$cuttable = mysql_fetch_assoc($cuttable_qry);



	echo $x= $cuttable['Table-2 field']; echo " ! ";
	echo $y= $cuttable['Table-2 field'];echo " ! ";
	echo $z= $cuttable['Table-2 field'];echo " ! ";
	
	
	$k = mysql_query("UPDATE `Table-1` SET `summary_style` = '$x', `summary_color` = '$y', `summary_customer` = '$z' WHERE `summary_laysheet_number` = $a;");

	if ($k) {
		echo "done";
	} else {
		echo mysql_error();
	}
	
	
}