MYSQL 在两种不同条件下对行进行计数，如果计数相等则返回值作为输出

Question

我有一张 table :

PRICE
ticker date      close
AAPL   3/20/2019 $100
AAPL   3/21/2019 $101.5
AAPL   3/22/2019 $106.5
GOOG   3/20/2019 $100
GOOG   3/21/2019 $130
GOOG   3/22/2019 $110
MSFT   3/20/2019 $184.5
MSFT   3/21/2019 $188.5
MSFT   3/22/2019 $210
IBM    3/20/2019 $72
IBM    3/21/2019 $70
IBM    3/22/2019 $10

我想知道在两种不同条件下比较行数的正确方法，并在计数相等时返回股票代码。 (最终只有当整个三月收盘价> 100 时才返回股票行情)。所以:

SELECT ticker, COUNT(*) FROM PRICE WHERE close>100 group by ticker;

返回:

| ticker | COUNT(*) |
+--------+----------+
| AAPL   |        2 |
| GOOG   |        2 |
| MSFT   |        3 |

还有

SELECT ticker, COUNT(*) FROM PRICE group by ticker;

返回:

| ticker | COUNT(*) |
+--------+----------+
| AAPL   |        3 |
| GOOG   |        3 |
| MSFT   |        3 |

因此 MSFT 应该是唯一返回输出的代码。

SQL 新手，如有任何建议，我们将不胜感激!

Answer 1

一种简单的方法按股票代码聚合并断言所有收盘价都大于 100:

SELECT ticker    -- maybe include COUNT(*), if you want to see the counts
FROM price
GROUP BY ticker
HAVING COUNT(CASE WHEN close <= 100 THEN 1 END) = 0;