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    <p>As long as no other joins have to be made dynamically to check the value of a parameter that might matter, and the only dynamic part is the WHERE clause, this could as well be a static query that has all possible parameters. So you have the following scenarios:</p> <p>In case you want to check values that can be everything (negative/nulls/zeros/positive/empty strings/etc), the use of an auxiliary parameter is needed, something like @signifficant_param1, along with the original value of @param1.</p> <pre><code>[...] WHERE (@signifficant_param1=0 or (@param1 is null and field1 is null) or @param1=field1) AND (@signifficant_param2=0 or (@param2 is null and field2 is null) or @param2=field2) //etc [...] </code></pre> <p>This is the most universal clause I could imagine. Basically it will verify the <code>@signifficant_param</code> value. If this parameter should be taken into account, it will be 1, the first part of the condition will be false and the second part (the verification of the parameter) will take place. In the second phase, if <code>@param</code> is null, then you are looking for all null values of <code>field</code>, and you can't compare null to null, because they are not equal. Then takes place the verification of regular non-null values match.</p> <p>If, on the other hand, the values in <code>field</code> can't be null, or can't be negative, you don't need the <code>@signifficant_param</code>, because you can make a rule, for example, if <code>@param</code> is null, then this value is not signifficant (in the previous case, you would have to search all null values instead), you could use the following:</p> <pre><code>[...] WHERE field1=case when @param1 is null then field1 else @param1 end --first way with case statement and (@param2 is null or field2=@param2) --second way with boolean logic [...] </code></pre>
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    1. PODrawbacks of Dynamic Query in Sqlserver 2005?
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    1. USAlexanderMP
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    1. COYou have to be really careful with this construct. Yes, it's an almost universal WHERE clause, but it's not, as they say, SARGable. That is, it's not going to be able to use your indexes effectively for processing your WHERE conditions. This is fine for filtering small subsets of data, but for a search of a large table, this is going to cause the database optimizer to scan.
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      1. USDave Markle
    2. CONice answer and nice comment too but i am agree with Dave markle that this is not efficient way to solve this problem.
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      1. USKuldipMCA
    3. COYes, it's partially true, but also you can't store queries larger than 8000 characters when building dynamic queries from inside MSSQL. It's PARTIALLY true, in my experience, because I had such algorithms on large tables (hundreds of millions of records), that WERE performing quite bad, because the table wasn't indexed on the fields that were needed. As soon as replication on another server was set up, I was able to run Database Engine Tuning Advisor, which proposed complex indexes and statistics, after which performance boosted by a coefficient of ~10. I say trying doesn't hurt.
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