MySQL get missing IDs from table

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I have this table in MySQL, for example:

ID | Name
1  | Bob
4  | Adam
6  | Someguy

If you notice, there is no ID number (2, 3 and 5).

How can I write a query so that MySQL would answer the missing IDs only, in this case: "2,3,5" ?

SELECT a.id+1 AS start, MIN(b.id) - 1 AS end
    FROM testtable AS a, testtable AS b
    WHERE a.id < b.id
    GROUP BY a.id
    HAVING start < MIN(b.id)

Hope this link also helps http://www.codediesel.com/mysql/sequence-gaps-in-mysql/

SQL: find missing IDs in a table, Here's the query for SQL Server: ;WITH Missing (missnum, maxid) AS ( SELECT 1 AS missnum, (select max(id) from @TT) UNION ALL SELECT missnum + 1, maxid FROM Missing WHERE missnum < maxid ) SELECT missnum FROM Missing LEFT OUTER JOIN @TT tt on tt.id = Missing. missnum WHERE tt.id is NULL OPTION (MAXRECURSION 0); Get missing id from table. Ask Question MySQL get missing IDs from table. Related. 2666. Add a column with a default value to an existing table in SQL Server. 886.

A more efficent query:

SELECT (t1.id + 1) as gap_starts_at, 
       (SELECT MIN(t3.id) -1 FROM my_table t3 WHERE t3.id > t1.id) as gap_ends_at
FROM my_table t1
WHERE NOT EXISTS (SELECT t2.id FROM my_table t2 WHERE t2.id = t1.id + 1)
HAVING gap_ends_at IS NOT NULL

How to find missing IDs in MySQL table, Using a Linux script populate a table test(id:auto-increment) up to your max value of your_table . Then execute something like select id from test  How can I write a query so that MySQL would answer the missing IDs only, in this case: "2,3,5" ? Answer 1 SELECT a.id+1 AS start, MIN(b.id) - 1 AS end FROM testtable AS a, testtable AS b WHERE a.id < b.id GROUP BY a.id HAVING start < MIN(b.id)

To add a little to Ivan's answer, this version shows numbers missing at the beginning if 1 doesn't exist:

SELECT 1 as gap_starts_at,
       (SELECT MIN(t4.id) -1 FROM testtable t4 WHERE t4.id > 1) as gap_ends_at
FROM testtable t5
WHERE NOT EXISTS (SELECT t6.id FROM testtable t6 WHERE t6.id = 1)
HAVING gap_ends_at IS NOT NULL limit 1
UNION
SELECT (t1.id + 1) as gap_starts_at, 
       (SELECT MIN(t3.id) -1 FROM testtable t3 WHERE t3.id > t1.id) as gap_ends_at
FROM testtable t1
WHERE NOT EXISTS (SELECT t2.id FROM testtable t2 WHERE t2.id = t1.id + 1)
HAVING gap_ends_at IS NOT NULL;

Compare two tables and return missing ids in MySQL?, To compare two tables and return missing ids, you need to use a subquery. The syntax is as follows −SELECT yourFirstTableName. Rather than returning multiple ranges of IDs, if you instead want to retrieve every single missing ID itself, each one on its own row, you could do the following: SELECT id+1 FROM table WHERE id NOT IN (SELECT id-1 FROM table) ORDER BY 1 The query is very efficient.

Above queries will give two columns so you can try this to get the missing numbers in a single column

select start from 
(SELECT a.id+1 AS start, MIN(b.id) - 1 AS end
    FROM sequence AS a, sequence AS b
    WHERE a.id < b.id
    GROUP BY a.id
    HAVING start < MIN(b.id)) b
UNION
select c.end from (SELECT a.id+1 AS start, MIN(b.id) - 1 AS end
    FROM sequence AS a, sequence AS b
    WHERE a.id < b.id
    GROUP BY a.id
    HAVING start < MIN(b.id)) c order by start;

SQL JOINs make it easy to find and fix missing data, How do I find missing records in a table in SQL? I have two simple tables: (here only the "id" column) table1: id 1 2 3 4 table2: id 2 4 the sql query should compare the two tables for missing "id" in table2 and

It would be far more efficient to get the start of the gap in one query and the end of the gap in one query.

I had 18M records and it took me less than a second each to get the two results. When I tried getting them together my query timed out after an hour.

Get the start of gap:

SELECT (t1.id + 1) as MissingID
FROM sequence t1
WHERE NOT EXISTS 
    (SELECT t2.id 
    FROM sequence t2 
    WHERE t2.id = t1.id + 1);

Get the end of gap:

SELECT (t1.id - 1) as MissingID
FROM sequence t1
WHERE NOT EXISTS 
    (SELECT t2.id 
    FROM sequence t2 
    WHERE t2.id = t1.id - 1);    

How to get missing values in sql?, rows that do not exist in the join table. An outer join will result in all rows of the left table, whether there is a match on the right one or not. Find ranges of missing values with subqueries. The above query identifies the start of ranges of missing numbers, but not the end. It also gives a false positive for 21, which is a missing number because it’s off the end of the whole sequence.

How to get missing values in row order?, edit: Corrected the query to return the first ID if not found, Since this answer, mySQL and MariaDB have added support for window functions  SQL JOINs make it easy to find and fix missing data. even though there is no corresponding record in the Donors table for someone with that ID number. SQL JOINs make it easy to find and

mysql: Re: Finding missing ID, Assuming by "files" you mean rows, and assuming a table named t1, a column in it named id, and you having done something like SELECT @idmax := MAX(  MySQL MySQLi Database To compare two tables and return missing ids, you need to use a subquery. The syntax is as follows − SELECT yourFirstTableName.yourIdColumnName FROM yourFirstTableName WHERE NOT IN(SELECT yourSecondTableName.yourIdColumnName FROM youSecondTableName);

MySQL get missing IDs from table, How can I write a query so that MySQL would answer the missing IDs only, in this case: “2,3,5” ? Answers: SELECT a.id+1 AS start, MIN(b.id)  For information on mysql_insert_id(), the function you use from within the C API, see Section 28.7.6.38, “mysql_insert_id()”. For information on obtaining the auto-incremented value when using Connector/J, see Retrieving AUTO_INCREMENT Column Values through JDBC.

Comments
  • This was genius! Thanks
  • Thanks Ivan. This runs so much quicker!
  • This worked for me, except that it missed the initial gap starting at id=1
  • MySQL returned an empty result set (i.e. zero rows). (Query took 60.3183 seconds.) -- It took just over a minute to check more than 2 million records.
  • Can you tweak this query so that it would return N missing IDs? I.e. - I would like to retrieve first 10 missing primary keys, ordered by their value. No need to report on all gaps.
  • With this one-column version, I get (for example) 475, 477, 506, 508, 513 but with the two-column version, it gets me the [475,475], [477,506], [508,513] which tells me I am missing numbers 475, 477-506, and 508-513.
  • Just a clarrification, I was suppose to have 18m records. It turns out I had only 3m records in my database and missed 15m records.