Mysql一行3个单引号
我遇到了下面的查询,它使用Mysql将行动态转换为列。有人知道3个单引号在Product_Name字段前后的作用吗Mysql一行3个单引号,mysql,syntax,quotes,Mysql,Syntax,Quotes,我遇到了下面的查询,它使用Mysql将行动态转换为列。有人知道3个单引号在Product_Name字段前后的作用吗 SET @sql = NULL; SELECT GROUP_CONCAT(DISTINCT CONCAT( 'count(case when Product_Name = ''', Product_Name, ''' then 1 end) AS ', replace(Product_Name, ' ', '')
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'count(case when Product_Name = ''',
Product_Name,
''' then 1 end) AS ',
replace(Product_Name, ' ', '')
)
) INTO @sql
from products;
SET @sql = CONCAT('SELECT pt.partner_name, ', @sql, ' from partners pt
left join sales s
on pt.part_id = s.partner_id
left join products pd
on s.product_id = pd.prod_id
group by pt.partner_name');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
说:
用'
引用的字符串中的'
可以写成'
手册上有很多例子