Question

我有这样的查询：

driver.find_element(:link_text, "Login").click

另一个像这样：

SELECT bgdepartemen.c_kodedept AS c_kodedept,
       bgdepartemen.vc_namadept AS vc_namadept,
       bgdivisi.c_kodediv AS c_kodediv,
       bgdivisi.vc_namadiv AS vc_namadiv,
       bggroup0.c_kodegrp0 AS c_kodegrp0,
       bggroup0.vc_namagrp0 AS vc_namagrp0,
       (SELECT COALESCE(SUM(bgbudget0.n_nilai))
        FROM (bgbudget0 JOIN bggroup1 ON bgbudget0.c_kodegrp1 = bggroup1.c_kodegrp1)
        WHERE bgbudget0.n_tahun = 2016 AND
              bgbudget0.n_bulan >= 2 AND
              bgbudget0.n_bulan <= 3 AND
              bgbudget0.c_kodediv = bgdivisi.c_kodediv AND
              bggroup1.c_kodegrp0 = bggroup0.c_kodegrp0 AND
              bggroup1.c_kodegrp1 LIKE '%') AS nilai
FROM bgdivisi JOIN bggroup0 ON 1 = 1
JOIN bgdepartemen on bgdivisi.c_kodedept = bgdepartemen.c_kodedept
WHERE bgdivisi.c_kodediv LIKE '%' AND
     bgdepartemen.c_kodedept LIKE '%' AND
     bggroup0.c_kodegrp0 LIKE '%'

我想从这些表中选择条件

SELECT bgdepartemen.c_kodedept AS c_kodedept,
       bgdepartemen.vc_namadept AS vc_namadept,
       bgdivisi.c_kodediv AS c_kodediv,
       bgdivisi.vc_namadiv AS vc_namadiv,
       bggroup0.c_kodegrp0 AS c_kodegrp0,
       bggroup0.vc_namagrp0 AS vc_namagrp0,
       (SELECT COALESCE(SUM(bgrealisasi0.n_nilai))
        FROM (bgrealisasi0 JOIN bggroup1 ON bgrealisasi0.c_kodegrp1 = bggroup1.c_kodegrp1)
        WHERE bgrealisasi0.n_tahun = 2016 AND
        bgrealisasi0.n_bulan >= 2 AND
        bgrealisasi0.n_bulan <= 3 AND
        bgrealisasi0.c_kodediv = bgdivisi.c_kodediv AND
        bggroup1.c_kodegrp0=bggroup0.c_kodegrp0 AND
        bggroup1.c_kodegrp1 LIKE '%') AS nilai
FROM bgdivisi JOIN bggroup0 ON 1 = 1
JOIN bgdepartemen on bgdivisi.c_kodedept = bgdepartemen.c_kodedept
WHERE bgdivisi.c_kodediv LIKE '%' AND
      bgdepartemen.c_kodedept LIKE '%' AND
      bggroup0.c_kodegrp0 LIKE '%'

但我也想更改出现0的空记录，我已尝试WHERE a.c_kodedept = b.c_kodedept AND a.c_kodediv = b.c_kodediv AND a.c_kodegrp0 = b.c_kodegrp0 AND (a.nilai is not null or b.nilai is not null)但它仍然没有给我正确的结果。

Answer 1

通常，您首先会将NULL值设置为0，然后将SUM设置为：

SELECT SUM(COALESCE(bgrealisasi0.n_nilai, 0)) ...

否则，您的查询会有一些缺陷，例如field LIKE '%'，这是一种写作field IS NOT NULL的效率非常低的方法。使用标量子查询会使整个查询真的难以阅读，如果重写为子查询，则可能会优化连接。

Answer 2

你应该使用

SELECT COALESCE(SUM(bgbudget0.n_nilai), 0) 
FROM .....
SELECT COALESCE(SUM(bgrealisasi0.n_nilai), 0) 
FROM ....

Answer 3

在 Postgres 从 9.4 版开始，SUM 忽略空值：

<块引用>

所有非空输入值的表达式总和

https://www.postgresql.org/docs/9.4/functions-aggregate.html

请注意，如果所有输入均为空，则聚合值将为空。

Answer 4

不是很明白你的问题是什么，但如果你想将null值更改为0可以参考下面的查询：

ISNULL(SUM(column_name), 0)

sql SUM：用0更改null

4 个答案: