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POIs LTRIM(RTRIM(COALESCE(TextField,''))) Bad?
primarykey
Id
768946
data
AcceptedAnswerId
768963
AnswerCount
6
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2009-04-20T16:08:39.390
FavoriteCount
0
LastActivityDate
2018-07-12T20:26:56.017
LastEditDate
2017-05-23T12:01:24.203
LastEditorUserId
-1
OwnerUserId
241536
ParentId
0
PostTypeId
1
Score
1
ViewCount
5013
LastEditorDisplayName
text
Body
I have a very high-traffic table with a <code>char(50)</code> field which takes part in several indexes. This <code>char(50)</code> field allows NULLS, and in that case a NULL value is considered to be the same as a non-NULL, zero-length string for my purposes. I also disregard leading & trailing whitespace and, while I scrub the data before I insert it, it may also be inserted by means beyond my control. I have a sproc that is used to copy data from one table to the main table, and it needs to be high-performance. I need to delete duplicate records before inserting the new data and I am using the method discussed <a href="https://stackoverflow.com/questions/714590/most-efficient-t-sql-delete-for-many-rows">in this thread</a> to perform the deletes. My delete statement looks like this (simplified): <pre><code>delete masterTable from masterTable t join incomingDataTable inc on ( LTRIM(RTRIM(COALESCE(inc.TextField,''))) = LTRIM(RTRIM(COALESCE(t.TextField,''))) ) where LTRIM(RTRIM(COALESCE(t.TextField,''))) <> '' </code></pre> I <a href="http://msdn.microsoft.com/en-us/library/aa964133(SQL.90).aspx" rel="nofollow noreferrer">have read</a> that constructs like LTRIM(RTRIM(...)) are bad. Can my delete statement be improved, and if so, how? EDIT: Just to clarify, <code>TextField</code> does take part in indexes on both tables. EDIT2: <code>TextField</code> is defined as <code>char(50)</code> in both tables. It is not of type <code>TEXT</code>.
Tags
<sql><sql-server><performance><tsql>
Title
Is LTRIM(RTRIM(COALESCE(TextField,''))) Bad?
singulars
PostAcceptedAnswerId
1. PO
 singulars
 PostTypePostTypeId
 PTAnswer
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USCommunity
UserOwnerUserId
1. USJohn Dibling
plurals
PostLinksPostIdRelatedPostId
1. PL
 singulars
 LinkTypeLinkTypeId
 LTLinked
2. PL
 singulars
 LinkTypeLinkTypeId
 LTLinked
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
 singulars
 PostTypePostTypeId
 PTAnswer
2. PO
 singulars
 PostTypePostTypeId
 PTAnswer
3. PO
 singulars
 PostTypePostTypeId
 PTAnswer
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 POIs LTRIM(RTRIM(COALESCE(TextField,''))) Bad?
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId
1. This table or related slice is empty.

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