Mysql中group_concat函数的妙用

我们在查询数据的时候，经常遇到一对多的表关系，对其进行多表关联查询，
但是在列表里面显示数据的时候需要根据一的表进行数据显示，同时在一行内显示多的数据。大概例子如下图所示

这时候我们可以使用group_concat进行数据查询的一些处理：

SELECT
    com.serial_number,
    cis.customer_type,
    cis.company_name,
    cis.`name`,
    cis.logo_pic,
    cba.contract,
    cba.telephone,
    cba.province,
    cba.city,
    cba.area,
    cba.address,
    group_concat(
        '{"pkProduct":"',cpm.pk_product,'","productName":"',cpm.product_name,'","productLogoPic":"',cpm.product_logo_pic,
        ',"retailPrice":',cpm.retail_price,',"productWeight":',cpm.product_weight,',"catalogName":"',cpm.catalog_name,
        '","productNum":"',coap.product_num,'","discountType":"',cpm.discount_type,'","enoughPrice":"',IFNULL(cpm.enough_price,""),
        '","subPrice":"',IFNULL(cpm.sub_price,""),'","enoughNum":"',IFNULL(cpm.enough_num,""),'","giveProductNum":"',
        IFNULL(cpm.give_product_num,""),'","giveProductName":"',IFNULL(cpm.give_product_name,""),'","giveProductLogoPic":"',
        IFNULL(cpm.give_product_logo_pic,""),'","discountPrice":"',IFNULL(cpm.discount_price,""),'"}'),
    com.pk_invoices,
    com.total_num,
    com.cost_num,
    com.order_status,
    com.real_num,
    com.pk_order,
    com.billing_status,
    ccb.code_type,
    ccb.bankcode
FROM
    cti_order_message com
INNER JOIN cti_bank_address cba ON cba.pk_bank_address = com.pk_bank_address
INNER JOIN cti_individual_customer cis ON cis.pk_customer = com.pk_customer
LEFT JOIN cti_customer_bankcode ccb ON com.pk_bank_code = ccb.pk_bankcode
LEFT JOIN cti_order_and_product coap ON com.pk_order = coap.pk_order
LEFT JOIN (
    SELECT
        pm.pk_product,
        pm.product_name,
        pm.product_logo_pic,    
        cpd.discount_type,
        cpd.enough_price,
        cpd.sub_price,
        cpd.enough_num,
        cpd.give_product_num,
        cpd.give_product_name,
        cpd.give_product_logo_pic,
        cpd.discount_price,pm.product_weight,pm.retail_price,cpc.catalog_name
    FROM
        cti_product_message pm
    LEFT JOIN (
        SELECT
            cpd.pk_product,
            cpd.discount_type,
            cpd.enough_price,
            cpd.sub_price,
            cpd.enough_num,
            cpd.give_product_num,
            cpm.product_name AS give_product_name,
            cpm.product_logo_pic AS give_product_logo_pic,
            cpd.discount_price
        FROM
            cti_product_discount cpd
        LEFT JOIN cti_product_message cpm ON cpd.give_pk_product = cpm.pk_product
        WHERE
            cpd.dr = 0
        AND cpd.start_date <= '2017-08-22 13:16:00'
        AND cpd.end_date >= '2017-08-22 13:16:00'
        AND cpd.use_status = 1
        AND (
            cpd.is_all_bank = 1
            OR (
                is_all_bank = 2
                AND FIND_IN_SET(
                    '40289f9a5d7d9602015d7d9baf000000',
                    pkBank
                )
            )
        )
    ) cpd ON pm.pk_product = cpd.pk_product
LEFT JOIN cti_product_catalog cpc ON cpc.pk_catalog = pm.pk_catalog
) cpm ON coap.pk_product = cpm.pk_product
WHERE
    com.dr = 0
AND com.order_status = 1
AND com.pk_order = '40289f9a5def7129015def728c310003'
GROUP BY
    com.pk_order;