Question

I’m beginner in SQL. I can’t find what is this line:

type in (N'P', N'PC')

What is in where clause: P, PC, U?

EDIT:

The full query is:

IF EXISTS (SELECT * 
             FROM sys.objects 
            WHERE object_id = OBJECT_ID(N'[dbo].SP_AUTHENTIFICATION]') 
              AND type in (N'P', N'PC'))

Answer 1

First off what Relational Database Management System?

However, I suspect that type is a column in a table or a variable in your stored procedure.

N, implies that you’re converting the next string to a nchar, nvarchar or nvarchar2 (depending on RDBMS). These are data-types that allow multi-byte characters.

'PC' and 'P' are strings.

Putting this all together you’re converting 'PC' and 'P' to a multi-byte character set and checking whether the column or variable type is the same as one of these strings.

in means that type can be the same as either 'PC' or 'P'.

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From your comment you’re using SQL-Server

You’re checking whether the object [dbo].[SP_AUTHENTIFICATION] exists and is a stored procedure (P) or a assembly stored procedure (PC).

The column type in sys.objects is not an nchar so the conversion is fairly pointless.

Going point by point

• IF EXISTS – If the result of the following query in brackets returns a row:
• SELECT * FROM sys.objects – Select a row from sys.objects
• WHERE object_id = – Where the object_id is equal to the following
• OBJECT_ID(N'[dbo].[SP_AUTHENTIFICATION]') – Return the object_id of [dbo].[SP_AUTHENTIFICATION]
• AND type in (N'P', N'PC') – and where that object is a stored procedure.

U, which isn’t in your query is checking to see whether the type is a table. The documentation gives you a full list.