user variables with ":="

[Odelaine]

Hi,

I've a big problem with setting user variables in MySQL.
Always when I try to use the syntax with ":", e.g. "SET @A := 1",
I get a strange error message (Exception EDatabaseError):
"Fehlender Wert fuer Parameter '='" --> "Missing value for parameter '='".

Example in Delphi:

SQLQLocalOnly.SQL.Add('SET @counter := 0; ');
SQLQLocalOnly.SQL.Add(
'UPDATE tbl1, ' +
'( ' +
'SELECT ' +
'(@counter := @counter+1) AS nummerierung, ... ' +
'FROM tbl3 ' +
'WHERE (...) ' +
'ORDER BY ... DESC ' +
') AS tbl2 ' +
'SET tbl1.platzierung = tbl2.nummerierung ' +
'WHERE (...) ';
SQLQLocalOnly.ExecSQL;

This example is working with phpMyAdmin properly, so Database and Statement should be OK.
All other MySQL-Statements are working properly with the corelab driver so far, so Installation should be OK.
In the first line I can use 'SET @counter = 0; ' instead of 'SET @counter := 0; ' which is working, but this syntax isn't allowed in the SELECT statement.

EDIT: I use dbexpmda.dll version 3.0 in TSQLConnection (Delphi 7.0)

Please give me any advices to solve this issue.

Best Regards
Ingolf

[Guest]

Hi,

I've a big problem with setting user variables in MySQL.
Always when I try to use the syntax with ":", e.g. "SET @A := 1",
I get a strange error message (Exception EDatabaseError):
"Fehlender Wert fuer Parameter '='" --> "Missing value for parameter '='".

Example in Delphi:

SQLQLocalOnly.SQL.Add('SET @counter := 0; ');
SQLQLocalOnly.SQL.Add(
'UPDATE tbl1, ' +
'( ' +
'SELECT ' +
'(@counter := @counter+1) AS nummerierung, ... ' +
'FROM tbl3 ' +
'WHERE (...) ' +
'ORDER BY ... DESC ' +
') AS tbl2 ' +
'SET tbl1.platzierung = tbl2.nummerierung ' +
'WHERE (...) ';
SQLQLocalOnly.ExecSQL;

This example is working with phpMyAdmin properly, so Database and Statement should be OK.
All other MySQL-Statements are working properly with the corelab driver so far, so Installation should be OK.
In the first line I can use 'SET @counter = 0; ' instead of 'SET @counter := 0; ' which is working, but this syntax isn't allowed in the SELECT statement.

EDIT: I use dbexpmda.dll version 3.0 in TSQLConnection (Delphi 7.0)

Please give me any advices to solve this issue.

Best Regards
Ingolf

[Antaeus]

Parameters are parsed by SQLQuery of dbExpress (in unit SqlExpr, TSQLQuery.QueryChanged method) but not by our driver. To prevent this behaviour you can set ParamCheck option of SQLQuery to False.

[Odelaine]

That easy is this!

Many Thanks for giving me this small, but vital hint.

Ingolf