Schreiben Sie den Titel um: So konvertieren Sie WITH `cte` AS (VALUES ROW(1), ROW(2), ROW(n)) in MySQL-Syntax in jOOQ DSL

Question

Ich habe eine SQL-Abfrage für MySQL:

WITH `cte` AS (
    ( SELECT 1431655747 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 1431655733 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 715827794 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 715827865 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 1073741809 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 1073741759 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 715827800 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 1431655693 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 715827789 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 715827838 AS `n` FROM DUAL ) UNION ALL
    ( SELECT 715827823 AS `n` FROM DUAL ) UNION ALL
( SELECT 858993391 AS `n` FROM DUAL )) SELECT
`cte`.`n`,
`maxmind_country`.`country`.`name_en` 
FROM
    `cte`
    JOIN `maxmind_country`.`ipv4` ON `cte`.`n` BETWEEN `maxmind_country`.`ipv4`.`start_int` 
    AND `maxmind_country`.`ipv4`.`last_int`
    JOIN `maxmind_country`.`country` ON `maxmind_country`.`country`.`geoname_id` = `maxmind_country`.`ipv4`.`v_geoname_id`;

Nach der Umstellung auf jOOQ DSL:

String ipAlias = "n";
SelectSelectStep<Record1<UInteger>> unionIps = ips
    .stream()
    .distinct()
    .map(value -> DSL.select(DSL.val(value).as(ipAlias)))
    .reduce((r1, r2) -> (SelectSelectStep<Record1<UInteger>>) r1.unionAll(r2))
    .orElse(null);

if(unionIps == null)
    return null;

CommonTableExpression<Record1<UInteger>> cte = DSL.name("cte").as(unionIps);
Field<UInteger> ipField = cte.field(ipAlias, UInteger.class);
return dslContext
    .with(cte)
    .select(ipField, COUNTRY.NAME_EN)
    .from(cte)
    .join(IPV4).on(ipField.between(IPV4.START_INT, IPV4.LAST_INT))
    .join(COUNTRY).on(COUNTRY.GEONAME_ID.eq(IPV4.V_GEONAME_ID))
    .fetchMap(ipField, Country.class);

Das Ergebnis ist:

+------------+----------------+
| n          | name_en        |
+------------+----------------+
| 1431655747 | Spain          |
| 1431655733 | Spain          |
|  715827794 | China          |
|  715827865 | China          |
| 1073741809 | United States  |
| 1073741759 | United States  |
|  715827800 | China          |
| 1431655693 | Spain          |
|  715827789 | China          |
|  715827838 | China          |
|  715827823 | China          |
|  858993391 | United Kingdom |
+------------+----------------+
12 rows in set (0.16 sec)

Aber die Erklärung zeigt eine überflüssige UNION:

id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1   PRIMARY <derived2>      ALL                 12  100,00  
1   PRIMARY ipv4        ALL ipv4_start_int_UNIQUE,ipv4_last_int_UNIQUE,ipv4_v_geoname_id_fk_idx             325934  11,11   Range checked for each record (index map: 0x7)
1   PRIMARY country     eq_ref  PRIMARY PRIMARY 4   maxmind_country.ipv4.v_geoname_id   1   100,00  
2   DERIVED                                     No tables used
3   UNION                                       No tables used
4   UNION                                       No tables used
5   UNION                                       No tables used
6   UNION                                       No tables used
7   UNION                                       No tables used
8   UNION                                       No tables used
9   UNION                                       No tables used
10  UNION                                       No tables used
11  UNION                                       No tables used
12  UNION                                       No tables used
13  UNION                                       No tables used

Ich habe eine SQL mit einer anderen MySQL-Syntax umgeschrieben – VALUES ROW(1), ROW(2), ROW(n):

WITH `cte` AS (
VALUES ROW(1431655747),
    ROW(1431655733),
    ROW(715827794),
    ROW(715827865),
    ROW(1073741809),
    ROW(1073741759),
    ROW(715827800),
    ROW(1431655693),
    ROW(715827789),
    ROW(715827838),
    ROW(715827823),
    ROW(858993391)) SELECT
`cte`.`column_0`,
`maxmind_country`.`country`.`name_en` 
FROM
    `cte`
    JOIN `maxmind_country`.`ipv4` ON `cte`.`column_0` BETWEEN `maxmind_country`.`ipv4`.`start_int` 
    AND `maxmind_country`.`ipv4`.`last_int`
    JOIN `maxmind_country`.`country` ON `maxmind_country`.`country`.`geoname_id` = `maxmind_country`.`ipv4`.`v_geoname_id`;

Gleiches Ergebnis:

+------------+----------------+
| column_0   | name_en        |
+------------+----------------+
| 1431655747 | Spain          |
| 1431655733 | Spain          |
|  715827794 | China          |
|  715827865 | China          |
| 1073741809 | United States  |
| 1073741759 | United States  |
|  715827800 | China          |
| 1431655693 | Spain          |
|  715827789 | China          |
|  715827838 | China          |
|  715827823 | China          |
|  858993391 | United Kingdom |
+------------+----------------+
12 rows in set (0.16 sec)

Aber der Abfrageplaner verwendet UNION nicht:

id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1   PRIMARY <derived2>      ALL                 12  100,00  
1   PRIMARY ipv4        ALL ipv4_start_int_UNIQUE,ipv4_last_int_UNIQUE,ipv4_v_geoname_id_fk_idx             325934  11,11   Range checked for each record (index map: 0x7)
1   PRIMARY country     eq_ref  PRIMARY PRIMARY 4   maxmind_country.ipv4.v_geoname_id   1   100,00  
2   DERIVED                                     No tables used

Frage: Wie konvertiert man das endgültige Skript in jOOQ DSL? Ich kann keine Möglichkeit finden, es zu tun

WITH `cte` AS (VALUES ROW(1), ROW(2), ROW(n)) ... ?

Answer 1

截至jOOQ 3.15版本，还没有办法将标准SQL VALUES构造器表示为org.jooq.Select。它只能表示为org.jooq.Table，请参见：https://github.com/jOOQ/jOOQ/issues/5871。

因此，您还不能使用jOOQ DSL表示完全符合要求的语法，但是您可以在FROM子句中使用VALUES：

selectFrom(values(...))

这应该会产生与您所期望的几乎相同的计划。另一种解决方法是使用纯SQL模板。