[mysql update column from another table] Coping info from specific colum from another table. #mysql,#PS17

file.sql

UPDATE ps_product_shop c
JOIN table_test e ON c.id_product = e.id_product
SET c.id_category_default = e.id_category_default

note: tested.

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

NOTE: IT CANT BE THE SAME TABLE.Use this for just 1 data and small DB

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Example with Join (more fast)
UPDATE tableB t1 
        INNER JOIN tableA t2 
             ON t1.name = t2.name
SET t1.value = t2.value