sql server (alternate): Replace Multiple LIKEs -- sql server (alternate)

Re: Replace Multiple LIKEs

Ed Murphy
9/30/2006 3:40:23 AM

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Normalize tblStuff by removing column Keyword and replacing it with a
second table tblStuffKeyword. For instance, instead of

create table tblStuff (
StuffKey int,
StuffField1 varchar(50),
StuffField2 varchar(50),
Keyword text
)

insert into tblStuff (StuffKey, StuffField1, StuffField2, Keyword)
values (1, 'A', 'B', '123456,321654,987987,345987')
insert into tblStuff (StuffKey, StuffField1, StuffField2, Keyword)
values (2, 'C', 'D', '')
insert into tblStuff (StuffKey, StuffField1, StuffField2, Keyword)
values (3, 'E', 'F', '123456,987987')

do this:

create table tblStuff (
StuffKey int,
StuffField1 varchar(50),
StuffField2 varchar(50)
)

create table tblStuffKeyword (
StuffKey int,
Keyword varchar(50)
)

insert into tblStuff (StuffKey, StuffField1, StuffField2)
values (1, 'A', 'B')
insert into tblStuff (StuffKey, StuffField1, StuffField2)
values (2, 'C', 'D')
insert into tblStuff (StuffKey, StuffField1, StuffField2)
values (3, 'E', 'F')

insert into tblStuffKeyword (StuffKey, Keyword)
values (1, '123456')
insert into tblStuffKeyword (StuffKey, Keyword)
values (1, '321654')
insert into tblStuffKeyword (StuffKey, Keyword)
values (1, '987987')
insert into tblStuffKeyword (StuffKey, Keyword)
values (1, '345987')
insert into tblStuffKeyword (StuffKey, Keyword)
values (3, '123456')
insert into tblStuffKeyword (StuffKey, Keyword)

Re: Replace Multiple LIKEs

laurenquantrell
9/30/2006 7:54:13 AM

Ed,
Thanks. However, rebuilding the database architecture is currently not
an option.
I need a way to improve performace of the query with the existing table
structure.
lq

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Re: Replace Multiple LIKEs

Dan Guzman
10/1/2006 1:29:28 PM

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There isn't much you can do because of the leading '%' in the LIKE
expressions. The only approach I can think of is to add a covering index on
the SomeColumnName, Keyword and Something columns. At least this will limit
the scan to the rows matching the SomeColumnName value specified.

Consider this a lesson on one of the many reasons why one shouldn't store a
delimited list in a relational table column.

--
Hope this helps.

Dan Guzman
SQL Server MVP

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Re: Replace Multiple LIKEs

laurenquantrell
10/1/2006 6:08:33 PM

Dan,
Thanks.

[quoted text, click to view]

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