mysql row transfer columns, functions GROUP_CONCAT (expr)

demo：

　　

 

 

Statement:

SELECT '行' id, '' product_name
UNION
SELECT id, product_name FROM `product` WHERE id < 5

result:

Line
1 ICBC
2 Test Test
3 1
4 laptops

 

 

Statement:

SELECT '行转列后' id, '' product_name
UNION
SELECT GROUP_CONCAT(id) id, GROUP_CONCAT(product_name) product_name FROM `product` WHERE id < 5

result:

After the line transfer columns
1,2,3,4 icbc, test test, 1 laptop

 

 

Statement:

SELECT '行' id, '' product_name
UNION
SELECT id, product_name FROM `product` WHERE id < 5
UNION
SELECT '行转列后' id, '' product_name
UNION
SELECT GROUP_CONCAT(id) id, GROUP_CONCAT(product_name) product_name FROM `product` WHERE id < 5

result:

Line
1 ICBC
2 Test Test
. 3 1
. 4 laptop
row after transfection, columns
1,2,3,4 icbc, test Test, 1, laptops

 

 

The official document: https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_group-concat