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Have picked up someone's code and this is a part of a where clause, anyone know what the double colon indicates?
b.date_completed > a.dc::date + INTERVAL '1 DAY 7:20:00' 
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The SQL IN condition (sometimes called the IN operator) allows you to easily test if an expression matches any value in a list of values. It is used to help reduce the need for multiple OR conditions in a SELECT, INSERT, UPDATE, or DELETE statement.
Double TypeDouble types are used when we are not certain of the behavior of our data. The input data is interpreted as floating point integer values. Some data may take more digits to the right of the decimal point. While the storage size of the decimal type is variable, the double type takes 8 bytes storage size.
@mario, "The curly braces are for complex variable expressions. They are interpreted by PHP, not by the SQL interface ".
It varies based on RDBMS, but if I guess right, that's PostgreSQL, in which case the :: converts a.dc to a date type of date.
In other flavors...
In MS SQL Server 2000:
For built-in user-defined functions that return a table, the function name must be specified with a leading double colon (::) to distinguish it from user-defined functions that are not built-in. It also must be specified as a one-part name with no database or owner qualifications. For example: SELECT * FROM ::fn_helpcollations() b.. For built-in user-defined functions that return a scalar value, the function name must be specified as a one-part name (do not specify database or owner). Do not specify a leading double colon (::).
In MS SQL Server 2005:
Double-colons are no longer required for UDFs that return a table.
However...
Double-colons are required in SQL Server 2005 when granting permissions on schemas, certificates, endpoints, and a few other securables.
As well as...
When using User-Defined Types, static methods of the type must be called using the double-colon syntax.
Sources: BOL and Kalen Delaney's Blog
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