SQLite - 帮助提高复杂查询的效率

Question

数据是财务数据，以存储桶的形式结构化，其中一个存储桶 (Rollup) 可以包含其他数据存储桶。作为示例结构：

Rollup1 | Dept1
Rollup1 | Rollup2 | Dept2
Rollup1 | Rollup2 | Dept3
Rollup1 | Rollup3 | Dept4
Rollup1 | Rollup3 | Rollup4 | Dept5
Rollup1 | Rollup3 | Rollup4 | Dept6

这有 8 列，Rollups 和 Depts 分散在各处（但叶子总是单个 Depts）。大约 10k 行。

查询结果的目标是显示包含所有汇总的单列，具有可变逻辑以正常显示某些汇总，并修改所有其他汇总。

例如，如果我的变量包含“Dept4”，我的结果将是：

Rollup1
Rollup3
NA - Rollup2
NA - Rollup4

在实际场景中，有 3 个变量决定 Rollup 列的显示。

这就是我所拥有的，它应该可以发挥作用，但是性能非常糟糕。 1 Query 最多需要 5 秒，我想改进一下。

SELECT DISTINCT CASE
   WHEN "2" NOT IN
      (
         SELECT "2"
         FROM "Finance New"
         WHERE (@VAR3 = 'All' OR @VAR3 IN ("2","3","4","5","6","7","8","9"))
         AND (@VAR4 = 'All' OR "10" = @VAR4)
         AND (@VAR5 = 'All' OR "11" = @VAR5)
         )
   THEN
      'Z N/A - ' || "2"
   ELSE
      "2"
   END AS COL2
FROM "Finance New"
WHERE "5" <> 'All Applicable' AND "1" <> '9999'
AND "2" LIKE '9%'

UNION

SELECT DISTINCT CASE
   WHEN "3" NOT IN
      (
         SELECT "3"
         FROM "Finance New"
         WHERE (@VAR3 = 'All' OR @VAR3 IN ("2","3","4","5","6","7","8","9"))
         AND (@VAR4 = 'All' OR "10" = @VAR4)
         AND (@VAR5 = 'All' OR "11" = @VAR5)
         )
   THEN
      'Z N/A - ' || "3"
   ELSE
      "3"
   END AS COL2
FROM "Finance New"
WHERE "5" <> 'All Applicable' AND "1" <> '9999'
AND "3" LIKE '9%'
UNION

Etc, for each of the columns in the Rollup/Dept Tree report.

每个联合查询中的内部选择根据可变条件附加到文本。排序是自动完成的。 UNION (AND "3" LIKE "9%") 之前的最后一行是实际抓取汇总。汇总均以 9 开​​头。

输入参数被标记为@VARx。

我想知道是否有更有效的方法来执行此操作，假设我无法创建临时表并且无法更改数据的结构。

谢谢！

Answer 1

1. 所有这些 OR 都阻止使用索引。 如果可能，请删除那些 @VAR = 'All' 比较（或其他比较）并根据实际的 VAR3/4/5 值动态创建 SQL 字符串。
2. LIKE 阻止使用索引（因为 LIKE（或 GLOB）需要索引列上的 TEXT 亲和性）。 将其替换为普通比较，即将"col" LIKE '9%' 替换为"col" >= '9' AND "col" < ':'。
3. UNION 已删除重复项；删除 DISTINCT。
4. 没有索引，所有这些查询都会进行全表扫描。 创建以下（覆盖）索引：

    CREATE INDEX i_10_11_all on "Finance New"("10","11", "2","3","4","5","6","7","8","9");
    CREATE INDEX i_11_10_all on "Finance New"("11","10", "2","3","4","5","6","7","8","9");
    CREATE INDEX i_2_1_5 on "Finance New"("2", "1","5");
    CREATE INDEX i_3_1_5 on "Finance New"("3", "1","5");
    -- and so on for 4..9