SQL Server full text search on column with alias - sql-server

Question

I am using full-text search, its working fine on a direct column of table but not on a derived/aliased column.
SELECT ExpectationId
,ExpectationName
,(
CASE
WHEN ExpectationOrganization_OrganizationId IS NOT NULL
THEN (
SELECT OrganizationName
FROM Organizations
WHERE OrganizationId = ExpectationOrganization_OrganizationId
)
WHEN ExpectationBeneficiary_BeneficiaryId IS NOT NULL
THEN (
SELECT BeneficiaryName
FROM Beneficiaries
WHERE BeneficiaryId = ExpectationBeneficiary_BeneficiaryId
)
ELSE (
SELECT TeamName
FROM Teams
WHERE TeamId = ExpectationTeam_TeamId
)
END
) AS ParentName
FROM Expectations
WHERE
FREETEXT(ExpectationName, #Keyword) ---Working
OR FREETEXT(ParentName, #Keyword) ---Not working
All these columns ExpectationName, OrganizationName, BeneficiaryName, TeamName are full-text indexed.
How can I make it work for ParentName column?

Answer 1

You need to create a VIEW based on your query first then add a Full-Text index to it which will include the ParentName column. Without the Full-Text index over a column being searched neither FREETEXT nor CONTAINS will work.
Something like that should help you:
CREATE VIEW ExpectationsView AS
SELECT ExpectationId
,ExpectationName
,(
CASE
WHEN ExpectationOrganization_OrganizationId IS NOT NULL
THEN (
SELECT OrganizationName
FROM Organizations
WHERE OrganizationId = ExpectationOrganization_OrganizationId
)
WHEN ExpectationBeneficiary_BeneficiaryId IS NOT NULL
THEN (
SELECT BeneficiaryName
FROM Beneficiaries
WHERE BeneficiaryId = ExpectationBeneficiary_BeneficiaryId
)
ELSE (
SELECT TeamName
FROM Teams
WHERE TeamId = ExpectationTeam_TeamId
)
END
) AS ParentName
FROM Expectations
GO
-- This index is needed for FTS index.
-- Note, I trust ExpectationId column is unique in your SELECT above,
-- if it's not, the below CREATE INDEX will fail and you will need to provide
-- a new column to your VIEW which will uniquely identify each row, then use
-- that PK-like column in the below index
CREATE UNIQUE CLUSTERED INDEX PK_ExpectationsView
ON ExpectationsView (ExpectationId);
GO
CREATE FULLTEXT CATALOG fts_catalog;
GO
CREATE FULLTEXT INDEX ON ExpectationsView
(
ExpectationName Language 1033,
ParentName Language 1033
)
KEY INDEX PK_ExpectationsView
ON fts_catalog;
WITH (CHANGE_TRACKING = AUTO)
GO
Once the Full-Text index which includes the relevant columns is there you can use FREETEXT or CONTAINS in queries:
SELECT ExpectationId, ExpectationName, ParentName FROM ExpectationsView
WHERE FREETEXT(ExpectationName, #Keyword) OR FREETEXT(ParentName, #Keyword)
Note, the above code I've provided off the top of my head because I don't have data schema for your case so couldn't try running it. However, it should give you the general idea on how to proceed. HTH.