SELECT中的SQL WHERE语句？

所以我尝试输出两列，它们调用相同的特性。除1列外，我希望值的计数小于5，另一列我希望值的计数大于5

SELECT COUNT (col_a) FROM table WHERE col_a < 5

这就是你如何得到第一个

但我想知道如何组合这两个查询。比如：

SELECT 
    COUNT(col_a WHERE col_a < 5) AS col_1, 
    COUNT(col_a WHERE col_a > 5) AS col_2 
FROM table

有什么想法吗？

试试这个

SELECT (
    SELECT COUNT(*)
    FROM table
    WHERE col_a < 5
)
, (
    SELECT COUNT(*)
    FROM table
    WHERE col_a < 5
)

试试这个

SELECT (
    SELECT COUNT(*)
    FROM table
    WHERE col_a < 5
)
, (
    SELECT COUNT(*)
    FROM table
    WHERE col_a < 5
)

---

您正在寻找条件聚合：

SELECT 
     SUM(CASE WHEN col_a < 5 THEN 1 ELSE 0 END) AS col_1, 
     SUM(CASE WHEN col_a > 5 THEN 1 ELSE 0 END) AS col_2 
FROM mytable

在MySQL中：

SELECT 
     SUM(col_a < 5) AS col_1, 
     SUM(col_a > 5) AS col_2 
FROM mytable

---

您正在寻找条件聚合：

SELECT 
     SUM(CASE WHEN col_a < 5 THEN 1 ELSE 0 END) AS col_1, 
     SUM(CASE WHEN col_a > 5 THEN 1 ELSE 0 END) AS col_2 
FROM mytable

在MySQL中：

SELECT 
     SUM(col_a < 5) AS col_1, 
     SUM(col_a > 5) AS col_2 
FROM mytable