[英]Count of empty values in string array in PostgreSQL
I want to check Projects column values have the same values for all the same values of PartNo and PartName columns.我想检查 Projects 列值对于 PartNo 和 PartName 列的所有相同值是否具有相同的值。 Projects column data type is character variyng[].
项目列数据类型是字符 variyng[]。 For example:
例如:
PartNo![]() |
PartName![]() |
Projects![]() |
---|---|---|
1 ![]() |
3 ![]() |
6;5 ![]() |
1 ![]() |
3 ![]() |
|
1 ![]() |
3 ![]() |
|
3 ![]() |
2 ![]() |
5;5 ![]() |
In this case, Projects have different values (6;5) and () for the same PartName(3) and PartNo(1).在这种情况下,对于相同的 PartName(3) 和 PartNo(1),Projects 具有不同的值 (6;5) 和 ()。
This is my query, but it does not work with empty character variyng[] in projects column!这是我的查询,但它不适用于项目列中的空字符 variyng[]!
SELECT COUNT(*) from (
select c.partno, c.partname
FROM unnest(items) as c
GROUP BY c.partno, c.partname
HAVING COUNT(distinct c.projects) > 1) as xxx
INTO errCount;
IF errCount > 0 THEN
RETURN QUERY
SELECT 0 as status, format('Projects value should be the same for all Codes of the Part No %s and Name %s',c.partno,c.partname) as message
FROM unnest(items) as c
GROUP BY c.partno, c.partname
HAVING COUNT(distinct c.projects) > 1
;
RETURN;
END IF;
In the case of two different values in projects (not empty array), it works.在项目中有两个不同值(不是空数组)的情况下,它有效。
you can use a query like this with您可以使用这样的查询
coalesce
合并
function to convert null in array[null]将数组[null]中的null转换为null的函数
WITH tt AS (
SELECT
partno,
partname,
COALESCE ( project, ARRAY [null] ) AS pro
FROM
tab1
) SELECT
*,
COUNT ( pro ) AS num
FROM
tt
GROUP BY
partno,
partname,
pro
to create test table:创建测试表:
CREATE TABLE "tab1" (
"pk" serial4 primary key,
"partno" int4,
"partname" int4,
"project" varchar[]
);
INSERT INTO "tab1" (partno,partname,project) VALUES ( 1, 3, '{6,5}');
INSERT INTO "tab1" (partno,partname,project) VALUES ( 1, 3, NULL);
INSERT INTO "tab1" (partno,partname,project) VALUES ( 1, 3, NULL);
INSERT INTO "tab1" (partno,partname,project) VALUES ( 3, 2, '{5,5}');
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