MySQL、Mariadb中GROUP_CONCAT 函數使用介紹

By:授客 QQ：1033553122

語法：

GROUP_CONCAT([DISTINCT] column_name [ORDER BY 序字段 ASC/DESC] [SEPARATOR '分隔符'])

注：測試時發現，排序似乎不起作用

實踐

構造數據：

CREATE TABLE tb_test(

order_id INT,

goods_id INT,

user_name VARCHAR(7)

);

INSERT INTO tb_test VALUES(1000000001, 1, '授客'), (1000000001, 2, '授客'), (1000000001, 3, '授客'),(1000000002, 4, '小謝'), (1000000002, 5, '小謝'), (1000000002, 6, '小謝');

SELECT * FROM tb_test;

例子1：

查詢每個用戶購買的商品(按user_name分組，顯示其購買的所有商品)

SELECT t1.`order_id` AS '訂單號',

t1.`user_name` AS '用戶名',

GROUP_CONCAT((CASE WHEN t1.`goods_id` = 1 THEN '小蘋果'

WHEN t1.`goods_id` = 2 THEN '雪梨'

WHEN t1.`goods_id` = 3 THEN '香蕉'

WHEN t1.`goods_id` = 4 THEN '小李子'

WHEN t1.`goods_id` = 5 THEN '芭樂'

WHEN t1.`goods_id` = 6 THEN '葡萄'

END)) AS '商品'

FROM tb_test t1

GROUP BY t1.`user_name`;

結果：

例子2：

查詢每個用戶購買的商品(按user_name分組，顯示其購買的所有商品)，商品之間用";"分隔

SELECT t1.`order_id` AS '訂單號',

t1.`user_name` AS '用戶名',

GROUP_CONCAT((CASE WHEN t1.`goods_id` = 1 THEN '小蘋果'

WHEN t1.`goods_id` = 2 THEN '雪梨'

WHEN t1.`goods_id` = 3 THEN '香蕉'

WHEN t1.`goods_id` = 4 THEN '小李子'

WHEN t1.`goods_id` = 5 THEN '芭樂'

WHEN t1.`goods_id` = 6 THEN '葡萄'

END) SEPARATOR ';') AS '商品'

FROM tb_test t1

GROUP BY t1.`user_name`;

結果：

例子3：

查詢每個用戶購買的商品(按user_name分組，顯示其購買的所有商品)，商品名稱不重復

SELECT t1.`order_id` AS '訂單號',

t1.`user_name` AS '用戶名',

GROUP_CONCAT((CASE WHEN t1.`goods_id` = 1 THEN '小蘋果'

WHEN t1.`goods_id` = 2 THEN '雪梨'

WHEN t1.`goods_id` = 3 THEN '香蕉'

WHEN t1.`goods_id` = 4 THEN '小李子'

WHEN t1.`goods_id` = 5 THEN '芭樂'

WHEN t1.`goods_id` = 6 THEN '葡萄'

END) ) AS '商品'

FROM tb_test t1

GROUP BY t1.`user_name`;

運行結果：

修改腳本如下：

SELECT t1.`order_id` AS '訂單號',

t1.`user_name` AS '用戶名',

GROUP_CONCAT(DISTINCT (CASE WHEN t1.`goods_id` = 1 THEN

'小蘋果'

WHEN t1.`goods_id` = 2 THEN '雪梨'

WHEN t1.`goods_id` = 3 THEN '香蕉'

WHEN t1.`goods_id` = 4 THEN '小李子'

WHEN t1.`goods_id` = 5 THEN '芭樂'

WHEN t1.`goods_id` = 6 THEN '葡萄'

END) ) AS '商品'

FROM tb_test t1

GROUP BY t1.`user_name`;

運行結果如下：

總結

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