我有一个令人讨厌的、令人讨厌的数据布局，我不得不使用它。我终于得到了一个使用 C# 的工作查询和一个 for 循环，一遍又一遍地执行相同的查询，但调整了哪些字段被调用，但现在我想知道是否可以使用 while 循环来做到这一点。我收到一个错误，我不确定是因为我使用 Faircom / C-tree 作为数据库，还是我的查询有问题。我通常是 Mysql 用户。
该表有 20 个我关心并希望提取到 csv 列表中的字段。它们是 codetype1-codetype20，我希望它像value1, value2, value3...现在这样我一次将它们全部取回。麻烦的是 codetype1 依赖于另一个字段来确定我去哪里查找该代码的信息，这就是 case 语句的原因。
DROP PROCEDURE IF EXISTS proc_loop_test;
CREATE PROCEDURE proc_loop_test()
SET @index = 1;
WHILE(@index < 21) DO
SELECT Replace(Concat(To_char(apptid), To_char(.@index) ), ' ', '') AS reference_id,
apptid AS a_reference_id,
CASE
WHEN c.ee > 0 THEN d.amt
ELSE insfee.amt
END AS amount,
CASE
WHEN c.ee > 0 THEN Rtrim(e.moneyname)
ELSE insname.namefeecatid
END AS moneyschedule_name,
CASE codetype@index
WHEN 1 THEN rtrim(a.descript)
ELSE rtrim(b.descript0)
END AS description,
CASE codetype@index
WHEN 1 THEN rtrim(a.abbrevdescript)
ELSE rtrim(b.abbrev0)
END AS abbreviated_description,
CASE codetype@index
WHEN 1 THEN rtrim(a.thiscode)
ELSE rtrim(b.thiscode0)
END AS code
FROM meetings
LEFT JOIN
(
SELECT admin.table2.procid,
admin.table2.this_code_id,
admin.v_table1.descript,
admin.v_table1.abbrevdescript,
admin.v_table1.thiscode
FROM admin.table2
INNER JOIN admin.v_table1
ON admin.table2.this_code_id = admin.v_table1.this_code_id) AS a
ON meetings.codeid@index = a.procid
LEFT JOIN
(
SELECT admin.v_table1.descript AS descript0,
admin.v_table1.abbrevdescript AS abbrev0,
admin.v_table1.thiscode AS thiscode0,
admin.v_table1.this_code_id
FROM admin.v_table1) AS b
ON meetings.codeid@index = b.this_code_id
LEFT JOIN
(
SELECT patid AS id,
ee
FROM admin.customer) AS c
ON meetings.patid = c.id
LEFT JOIN
(
SELECT this_code_id AS redid,
eecategoryid,
amt
FROM admin.eeule) AS d
ON c.ee = d.eecategoryid
AND d.redid = b.this_code_id
LEFT JOIN
(
SELECT eecategoryid AS namefeecatid,
moneyname
FROM admin.eeulenames) AS e
ON d.eecategoryid = e.namefeecatid
LEFT JOIN (SELECT pi.customer_id,
pi.primarykk_id AS picid,
pi.primarykk_name,
pi.first_name,
pi.last_name,
i.groupname,
i.ee
FROM admin.v_pir AS pi
LEFT JOIN admin.money AS i
ON pi.primarykk_id = i.insid) AS
ins
ON ins.customer_id = c.id
LEFT JOIN (SELECT this_code_id AS redid,
eecategoryid,
amt
FROM admin.eeule) AS insfee
ON ins.ee = insfee.eecategoryid
AND insfee.redid = b.this_code_id
LEFT JOIN (SELECT eecategoryid AS namefeecatid,
moneyname
FROM admin.eeulenames) AS insname
ON insfee.eecategoryid = insname.namefeecatid
WHERE codeid@index >= 1
END WHILE;
END;
我从来没有使用过while循环，虽然我有点理解我应该选择它来进入某些东西，我是否需要创建一个临时表，或者它可以全部存储在内存中直到循环结束并返回.
值得一提的是，当您将 SELECT 替换为@index连接格式时，整个 SELECT 查询都可以在 C# 中工作" . index . "