Not like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.
When you concatenate strings, you cause problems because SQL receives commands like:
SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'
The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:
SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;
Which SQL sees as three separate commands:
SELECT * FROM MyTable WHERE StreetAddress = 'x';
A perfectly valid SELECT
DROP TABLE MyTable;
A perfectly valid "delete the table" command
And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.
So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?
And then there is your DB design ... oh dear. Part of why your query is so ugly and difficult to work out is that you are storing everything as strings. That's bad - very bad - and you need to fix that throughout your app as well. Always store data in the appropriate formats: numbers go in INT, DECIMAL, or FLOAT columns, Dates go in DATE, DATETIME, or DATETIME2 for example. If you don;t you make your job a whole load more complex as you have already seen with this task.
When you've fixed that through your whole app, you can start looking at how to fix the problem you have noticed - but there is no point in trying until you have!
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