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feat: update sql solution to lc problem: No.1398 (doocs#1780)

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Lines changed: 9 additions & 6 deletions

Original file line number	Diff line number	Diff line change
`@@ -85,20 +85,23 @@ Orders table:`
`85`	`85`
`86`	`86`	`<!-- 这里可写通用的实现逻辑 -->`
`87`	`87`
	`88`	`+方法一:LEFT JOIN + GROUP BY + HAVING`
	`89`	`+`
	`90`	+我们可以用 `LEFT JOIN` 将 `Customers` 表和 `Orders` 表连接起来,然后按照 `customer_id` 进行分组,最后筛选出购买了产品 A 和产品 B 却没有购买产品 C 的顾客。
	`91`	`+`
`88`	`92`	`<!-- tabs:start -->`
`89`	`93`
`90`	`94`	`### SQL`
`91`	`95`
`92`	`96`	```sql
`93`	`97`	`# Write your MySQL query statement below`
`94`		`-SELECT`
`95`		`- customer_id,`
`96`		`- customer_name`
	`98`	`+SELECT customer_id, customer_name`
`97`	`99`	`FROM`
`98`		`- Orders`
`99`		`- JOIN Customers USING (customer_id)`
	`100`	`+ Customers`
	`101`	`+ LEFT JOIN Orders USING (customer_id)`
`100`	`102`	`GROUP BY 1`
`101`		`-HAVING sum(product_name = 'A') > 0 AND sum(product_name = 'B') > 0 AND sum(product_name = 'C') = 0;`
	`103`	`+HAVING sum(product_name = 'A') > 0 AND sum(product_name = 'B') > 0 AND sum(product_name = 'C') = 0`
	`104`	`+ORDER BY 1;`
`102`	`105`	```
`103`	`106`
`104`	`107`	`<!-- tabs:end -->`

Lines changed: 9 additions & 6 deletions

Original file line number	Diff line number	Diff line change
`@@ -79,20 +79,23 @@ Orders table:`
`79`	`79`
`80`	`80`	`## Solutions`
`81`	`81`
	`82`	`+Solution 1: LEFT JOIN + GROUP BY + HAVING`
	`83`	`+`
	`84`	+We can use `LEFT JOIN` to join the `Customers` table and the `Orders` table, then group them by `customer_id`, and finally filter out the customers who have purchased products A and B but not product C.
	`85`	`+`
`82`	`86`	`<!-- tabs:start -->`
`83`	`87`
`84`	`88`	`### SQL`
`85`	`89`
`86`	`90`	```sql
`87`	`91`	`# Write your MySQL query statement below`
`88`		`-SELECT`
`89`		`- customer_id,`
`90`		`- customer_name`
	`92`	`+SELECT customer_id, customer_name`
`91`	`93`	`FROM`
`92`		`- Orders`
`93`		`- JOIN Customers USING (customer_id)`
	`94`	`+ Customers`
	`95`	`+ LEFT JOIN Orders USING (customer_id)`
`94`	`96`	`GROUP BY 1`
`95`		`-HAVING sum(product_name = 'A') > 0 AND sum(product_name = 'B') > 0 AND sum(product_name = 'C') = 0;`
	`97`	`+HAVING sum(product_name = 'A') > 0 AND sum(product_name = 'B') > 0 AND sum(product_name = 'C') = 0`
	`98`	`+ORDER BY 1;`
`96`	`99`	```
`97`	`100`
`98`	`101`	`<!-- tabs:end -->`

Lines changed: 5 additions & 6 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,9 +1,8 @@`
`1`	`1`	`# Write your MySQL query statement below`
`2`		`-SELECT`
`3`		`- customer_id,`
`4`		`- customer_name`
	`2`	`+SELECT customer_id, customer_name`
`5`	`3`	`FROM`
`6`		`- Orders`
`7`		`- JOIN Customers USING (customer_id)`
	`4`	`+ Customers`
	`5`	`+ LEFT JOIN Orders USING (customer_id)`
`8`	`6`	`GROUP BY 1`
`9`		`-HAVING sum(product_name = 'A') > 0 AND sum(product_name = 'B') > 0 AND sum(product_name = 'C') = 0;`
	`7`	`+HAVING sum(product_name = 'A') > 0 AND sum(product_name = 'B') > 0 AND sum(product_name = 'C') = 0`
	`8`	`+ORDER BY 1;`

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