MYSQL：喜歡的子查詢

Question

大家好，我想知道如何在總人數上實現目標

這是查詢

SELECT 
     field1,
     field2,
     (select count(*) 
       from table2 as t2 
       where t2.field5 LIKE '%' + t1.field2 + '%') as total_row 
FROM table1 as t1 ORDER BY total_row DESC

我想知道如何嵌入類似的陳述，因為field5具有一個或多個以逗號分隔的數據作為字符串

例如 field5具有“貓，狗，鼠標”

因此，field2正在尋找“ dog”之類的總行

希望你能幫助我。

Answer 1

假設逗號后面沒有空格，則需要執行以下操作：

select field1, field2, (
        select count(*)
        from table2 as t2
        where t2.field5 = t1.field2
            or t2.field5 like t1.field2 + ',%'
            or t2.field5 like '%,' + t1.field2 + ',%'
            or t2.field5 like '%,' + t1.field2
        ) as total_row
from table1 as t1
order by total_row desc

Answer 2

在每個字段的前面和后面串聯逗號：

SELECT field1
      ,field2
      ,( SELECT COUNT(*) 
         FROM table2 as t2 
         WHERE ','+t2.field5+',' LIKE '%,' + t1.field2 + ',%') as total_row 
FROM table1 as t1 ORDER BY total_row DESC

不知道上面的是否在MySQL中有效，可能需要CONCAT() ：

SELECT field1
      ,field2
      ,( SELECT COUNT(*) 
         FROM table2 as t2 
         WHERE CONCAT(',',t2.field5,',') LIKE CONCAT('%,',t1.field2,',%') as total_row 
FROM table1 as t1 ORDER BY total_row DESC