How do I create an index inside a stored procedure? - sql

Question

How do I create an index inside a stored procedure? It complains
Msg 102, Level 15, State 1, Procedure createIndexModifiedOn, Line 12
Incorrect syntax near 'PRIMARY'.
But ON [PRIMARY] is what SQL Server itself uses if you create a new index and select Script As New Query.
If I remove ON [PRIMARY] then it gives this error
Msg 102, Level 15, State 1, Procedure createIndexModifiedOn, Line 12
Incorrect syntax near ')'.
Here is the procedure:
create proc [dbo].createIndexModifiedOn
#table char(256)
as begin
declare #idx char(256)
set #idx = 'idx_' + SUBSTRING(#table, 7, len(#table)-1) + '_modified_on';
IF EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(#table) AND name = #idx)
DROP INDEX [#idx] ON [#table]
CREATE NONCLUSTERED INDEX [#idx] ON [#table]
(
[modified_on] ASC
) ON [PRIMARY]
go
This ended up being the full query:
create proc [dbo].createIndexModifiedOn
#table varchar(256)
as
declare #idx varchar(256);
declare #sql nvarchar(999);
set #idx = 'idx_' + SUBSTRING(#table, 8, len(#table)-8) + '_modified_on';
set #sql = '
IF EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(''' + #table + ''') AND name = ''' + #idx + ''')
DROP INDEX [' + #idx + '] ON ' + #table + '
CREATE NONCLUSTERED INDEX [' + #idx + '] ON ' + #table + '
(
[modified_on] ASC
) ON [PRIMARY]
';
print #table + ', ' + #idx;
BEGIN TRY
EXEC sp_executesql #sql;
END TRY
BEGIN CATCH
PRINT 'errno: ' + ltrim(str(error_number()))
PRINT 'errmsg: ' + error_message()
END CATCH
GO
EXEC sp_MSforeachtable 'exec createIndexModifiedOn "?"'

Answer 1

You can't use variables in the CREATE INDEX statement as you have. To do this, you will need to generate a SQL string and execute it with sp_executesql.
Freehand example:
DECLARE #sql NVARCHAR(1024);
SET #sql = 'CREATE NONCLUSTERED INDEX [' + #idx + '] ON [' + #table + ']
(
[modified_on] ASC
) ON [PRIMARY];';
EXEC sp_executesql #sql;