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How Can I Use The TQuery

Posted on 1999-01-05
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Last Modified: 2010-04-04
Hello!!
I want to do query to a table. Can you show me some examples

Thanks...
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Question by:mummi
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3 Comments
 
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Expert Comment

by:kretzschmar
ID: 1354652
hi mummi,

an example,

  query1.sql.Clear; {Deletes the sql-statement of your query}
  query1.sql.add('Select * from Sampletable where Samplefield =' + Yoursamplevalue.asstring; {Add a sql-statement}
try
  query1.open; {opens the query}
except  
  {opening-error occured - your errorhandling}
end;

a datasource connected to the tquery and a dbgrid connected on the datasource and you will see the resultset of your query.
Can handled as a table, except writeback can only done with simple sql-statements (property requestlive = true).

another example

  query1.sql.Clear; {Deletes the sql-statement of your query}
  query1.sql.add('Delete  from Sampletable where Samplefield =' + Yoursamplevalue.asstring; {Add a sql-statement}
try
  query1.execsql; {execute sql-statement -> no resultset}
except  
  {execution-error occured - your errorhandling}
end;

this are simple examples, and if you know about sql, then you can do many things with tquery.

the sql-statementsyntax depends on the database, where you will do a query to the tables in it(paradox, oracle, access ...).

meikl
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Accepted Solution

by:
mjustin earned 200 total points
ID: 1354653
with Query do
try
    // optional: for SQL server databases
    // if not Prepared then Prepare;
    Close; // in case it is already opened
    SQL.Text := 'your SQL commands go here';
    Open;
    // use it, print it...
finally
    Close;
end;
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Author Comment

by:mummi
ID: 1354654
Thanks...
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