[英]How to find gaps in sequential numbering in HSQLDB?
I'm trying to adapt this answer made for MySQL to HSQLDB (2.4.0, through Hibernate 5.2.12). 我正在尝试将针对MySQL的答案改编为HSQLDB(2.4.0,通过Hibernate 5.2.12)。 I have replaced MySQL "IF" function by "CASE WHEN" calls as follows:
我用“ CASE WHEN”调用替换了MySQL的“ IF”函数,如下所示:
SELECT
CONCAT(z.expected, CASE WHEN z.got-1>z.expected THEN CONCAT(' thru ',z.got-1) ELSE '' END) AS missing
FROM (
SELECT
@rownum\\:=@rownum+1 AS expected,
CASE WHEN @rownum=id THEN 0 ELSE @rownum\\:=id END AS got
FROM
(SELECT @rownum\\:=0) AS a
JOIN Notices
WHERE fonds_cote = '1Fi'
ORDER BY id
) AS z
WHERE z.got!=0;
The :
are escaped to avoid a parsing error from Hibernate. :
被转义以避免来自Hibernate的解析错误。 Still, it does not work and I face: 尽管如此,它仍然无法正常工作,我面临:
org.hsqldb.HsqlException: unexpected token: (
at org.hsqldb.error.Error.parseError(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserBase.unexpectedToken(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.XreadSelect(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.XreadQuerySpecification(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.XreadSimpleTable(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.XreadQueryPrimary(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.XreadQueryTerm(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.XreadQueryExpressionBody(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.XreadQueryExpression(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserDQL.compileCursorSpecification(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserCommand.compilePart(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.ParserCommand.compileStatement(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.Session.compileStatement(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.StatementManager.compile(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.Session.execute(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.jdbc.JDBCPreparedStatement.<init>(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hsqldb.jdbc.JDBCConnection.prepareStatement(Unknown Source) ~[hsqldb-2.4.0.jar:2.4.0]
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$5.doPrepare(StatementPreparerImpl.java:146) ~[hibernate-core-5.2.12.Final.jar:5.2.12.Final]
What is the correct syntax? 正确的语法是什么? Or is there a better way to do it in HSQLDB?
还是在HSQLDB中有更好的方法?
The problem is the use of the variable @rownum
. 问题是使用变量
@rownum
。 This is not supported by HSQLDB. HSQLDB不支持此功能。
With HSQLDB you can do it in a simple manner. 使用HSQLDB,您可以以简单的方式完成此操作。
Suppose the table is called CUSTOMER and the sequence column is called ID. 假设该表称为CUSTOMER,而序列列称为ID。 The queries below show how SEQUENCE_ARRAY works and is used for finding the missing values.
以下查询显示了SEQUENCE_ARRAY的工作方式,并用于查找缺失值。
-- this returns consecutive numbers within a fixed range
SELECT * FROM UNNEST (SEQUENCE_ARRAY(1, 1000, 1))
-- this returns all the possible consecutive numbers for an existing table
SELECT * FROM UNNEST (SEQUENCE_ARRAY((SELECT MIN(ID) FROM CUSTOMER), (SELECT MAX(ID) FROM CUSTOMER), 1))
-- this returns the list of unused IDs.
SELECT * FROM UNNEST (SEQUENCE_ARRAY((SELECT MIN(ID) FROM CUSTOMER), (SELECT MAX(ID) FROM CUSTOMER), 1)) SEQ(IDCOL)
LEFT OUTER JOIN CUSTOMER ON CUSTOMER.ID = SEQ.IDCOL WHERE CUSTOMER.ID IS NULL
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