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PostgreSQL Reference Manual - Volume 1 - SQL Language Reference
by The PostgreSQL Global Development Group
Paperback (6"x9"), 716 pages
ISBN 0954612027
RRP £32.00 ($49.95)

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6.10.5 Searching in Arrays

To search for a value in an array, you must check each value of the array. This can be done by hand, if you know the size of the array. For example:

SELECT * FROM sal_emp WHERE pay_by_quarter[1] = 10000 OR
                            pay_by_quarter[2] = 10000 OR
                            pay_by_quarter[3] = 10000 OR
                            pay_by_quarter[4] = 10000;

However, this quickly becomes tedious for large arrays, and is not helpful if the size of the array is uncertain. An alternative method is described in section 7.17 Row and Array Comparisons. The above query could be replaced by:

SELECT * FROM sal_emp WHERE 10000 = ANY (pay_by_quarter);

In addition, you could find rows where the array had all values equal to 10000 with:

SELECT * FROM sal_emp WHERE 10000 = ALL (pay_by_quarter);

Tip: Arrays are not sets; searching for specific array elements may be a sign of database misdesign. Consider using a separate table with a row for each item that would be an array element. This will be easier to search, and is likely to scale up better to large numbers of elements.

ISBN 0954612027PostgreSQL Reference Manual - Volume 1 - SQL Language ReferenceSee the print edition