Finding Where Clause Criteria in SQL Queries - sql

Question

I have a Table which has 3 different Select queries.
e.g.
Staff
------------------------------------------------------------
ID Code Name Phone DOB Email Addr1 Addr2 Addr3
Query1
Select ID, Code, Phone From Staff Where Code = 'ABC'
Query2
Select ID, Code, Phone From Staff Where Name = 'ABCXYZ' And Code = 'B'
Query3
Select ID, Code, Phone From Staff Where Phone= '1234' And Email = 'a#b'
These 3 queries are there in 3 different stored procedure.
I want to find the names of Attributes which i have used in all my Where clauses. But want to Automate this as I have more than 100 tables to look for
Something like this
exec fxGetWhereColList ('Staff');
Result:
Code
Name
Phone
Email

Answer 1

I agree with all posts before, it's a complex case.
I post you a small idea to help you in your work.
If you can retrieve each execution plan, you can parse XML result and get the impacted columns.
For example: On the node <Predicate>

Answer 2

Like Lamak says, doing this right is nearly impossible, at least in SQL.
To do it properly you should use a SQL Parser for the SQL variant you are using. A SQL Parser will identify the objects referenced in the statement, and the elements of the where clauses.
But if you know that the queries are simple and look like the one you are listing, you can use some simple queries to pick apart the statements. I have made an example for a single statement:
declare
#foo nvarchar(max)=N'Select ID, Code, Phone From Staff Where Phone= ''1234'' And Email = ''a#b'' '
, #From nvarchar(max)=' From '
, #Table nvarchar(max)
declare #a int
-- find FROM
set #a= PATINDEX('%'+#From+'%',#foo)
-- Find statement to the right of from
set #foo=ltrim(RIGHT(#foo,len(#foo)-(#a)))
-- Find first space
set #a=CHARINDEX(' ',#foo)
-- find first word, we assume it is the table name
set #Table=ltrim(rtrim(LEFT(#foo,#a)))
-- Find WHERE statement
set #foo=ltrim(rtrim(replace(right(#foo,len(#foo)-#a),'Where','')))
-- Now find matching columns in table, I am using SQL Server so I look up column names in information_schema.columns
select #Table,column_name
from INFORMATION_SCHEMA.COLUMNS
--from (values ('ID'),('Code'),('Name'),('Phone'),('DOB'),('Email'),('Addr1'),('Addr2'),('Addr3'))cols(column_name)
where TABLE_NAME=#table
and #foo like '%'+column_name+'%'
This solution will only work for some simple statements, it assumes a lot of stuff.