用php将数据从mysql表插入到另一个表中，跳过已经存在的表

Question

使用php将mysql表中的数据插入到另一个表中，跳过已经存在的数据

大家好，我解决不了我的这个问题:

我有两个表:

table_1 (id, cod。产品，颜色，价格，id_supplier)

table_2 (id_supplier, cod。产品，颜色，价格)

我想将table_2的数据插入到table_1，只有当table_2的id_supplier不存在于table1的id_supplier

我尝试了几个查询:

与

INSERT INTO table_1 (cod.products, color, price, id_supplier) 
SELECT cod.products, color, price, id_supplier FROM table_2

我插入的所有东西都没有考虑到id_provider…

where where子句不起作用

INSERT INTO table_1 (cod.products, color, price, id_supplier) 
SELECT cod.products, color, price, id_supplier FROM table_2 
WHERE table_1.id_supplier <> table_1.id_supplier

Answer 1

WHERE table_1.id_supplier <> table_1.id_supplier

改变

WHERE table_2.id_supplier NOT IN (SELECT id_supplier FROM table_1 GROUP BY id_supplier)

Answer 2

使用NOT IN运算符

INSERT INTO table_1 (cod.products, color, price, id_supplier) 
SELECT cod.products, color, price, id_supplier 
FROM table_2 where id_supplier not in (select distinct id_supplier from table_1)
;