I have a problem in this query:
string sqlString = "DELETE FROM [upload_news] WHERE (SELECT TOP " + no_of_recordss + " * FROM [upload_news] WHERE [country]='" + countryy.Text + "')";
Error Message :
Error: {"An expression of non-boolean type specified in a context
where a condition is expected, near ')'."}
How can i fix this ?
In the where clause you need a boolean expression.
Moreover, mysql doesn't support select top, you have to use limit instead and you can use it directly on delete
So your query should be:
delete from upload_news
where country=<SOME_COUNTRY> limit <NO_OF_RECORDS>
You have to replace values within "<>" with your desired values.
Or in your "strange" syntax:
string sqlString = "DELETE FROM [upload_news] WHERE [country]='" + countryy.Text + "' limit "+no_of_recordss;
Related
I am trying to multiply a row by a variable (calculated amount):
double servingsMultiplier = 1;
double servingSizeMultiplier = 1;
Calculate the values for "servingsMultiplier" and "servingSizeMultiplier".
String selectQry5 = ("SELECT ci_id, cr_id, ci_ingedient, (ci_amount*servingsMultiplier) AS ci_amount, " +
" (ci_unit*servingSizeMultiplier) AS ci_unit " +
" FROM at_cat_ingredient " +
" WHERE cr_id = ? " +
" ORDER BY ci_ingedient;");
The above works when I use a constant (e.g., 2); however, not when I use a variable. I get the error message:
"SQLException in recipePDF:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown
column 'servingsMultiplier' in 'field list'.
An identifier like servingsMultiplier inside the sql statement is not recognized as the value of the variable but as a column name, which of course does not exist.
Use ? placeholders for servingsMultiplier and servingSizeMultiplier in the statement and pass their values just like you pass the parameter in the WHERE clause:
String selectQry5 =
"SELECT ci_id, cr_id, ci_ingedient, " +
"(ci_amount * ?) AS ci_amount, " +
"(ci_unit * ?) AS ci_unit " +
"FROM at_cat_ingredient " +
"WHERE cr_id = ? " +
"ORDER BY ci_ingedient;";
If you want to use mysql variables, then add # before variable name.
SELECT ci_id, cr_id, ci_ingedient, (ci_amount*#servingsMultiplier) AS ci_amount,
(ci_unit*#servingSizeMultiplier) AS ci_unit
FROM at_cat_ingredient
WHERE cr_id = #id
ORDER BY ci_ingedient;
Get an error when writing to the database
The function for it:
var newMsg = { payload: msg.payload };
newMsg.topic="insert into MyTable (a,b,c,d,e,f,g) values (newMsg.payload)"
The incoming payload debug shows
payload: "B0:AC:A2:AC:07:F4","Ready","893901","860990","online","876","333"
The error I get from the database node (nore-red-node-mysql) is
"Error: ER_WRONG_VALUE_COUNT_ON_ROW: Column count doesn't match value
count at row 1"
The strange thing to me is that if I try a
newMsg.topic="insert into MyTable (a,b,c,d,e,f,g) values (\"B0:AC:A2:AC:07:F4\",\"Ready\",\"893901\",\"860990\",\"online\",\"876\",\"333\")"
it works perfectly...
Where is the trick?
There is no trick.
This is because the node-red-node-mysql and node-red-contrib-sqldbs nodes do not do any query substitution.
This means that what gets sent to the database is exactly what is in the msg.topic field. In this case that would have been:
insert into MyTable (a,b,c,d,e,f,g) values (newMsg.payload)
Which mysql will read as trying to pass a single value to a query expecting 7 values.
You will have to build the full query (and do your own variable escaping if needed) in a function node before passing the message to the database node.
at the end I solved it this way:
var data = msg.payload.split(",");
msg.payload = {};
msg.payload.a=data[0];
msg.payload.b=data[1];
msg.payload.c=data[2];
msg.payload.d=data[3];
msg.payload.e=data[4];
msg.payload.f=data[5];
msg.payload.g=data[6];
insert into MyTable (a,b,c,d,e,f,g) values ('" + data[0] + "','" + data[1] + "','" + data[2] + "','" + data[3] + "','" + data[4] + "','" + data[5] + "','" + data[6] + "')";
return msg;
When I use this query
("SELECT id, at_date AS MyDate , nom, pax, SUM(prix*pax) AS somme,
SUM(pax) AS totpax
FROM atelier ORDER BY " + Order_by + " " + SortDir + " LIMIT #Myid," +
PublicVariables.MySqlLimit, conn)
This gives an error here
_listBox[1].Items.Add(Convert.ToDateTime(reader["MyDate"]).ToString("d"));
Because there is NO ROWS int the table. Table is EMPTY.
But when I supress SUM(prix*pax) AS somme and SUM(pax) AS totpax from the query, reader does not read and no error occurs.
Is there any trick of MySql in there ?
I resolved the probleme by checking the table if there is any rows before calling this method but it's not what I like any idea ?
Use Group by clause for all non aggregate function before order by clause:
group by id,MyDate,nom,pax
I need help.... I am not good at SQL I get this error when I try to apply a JOIN:
[ Token line number = 1,Token line offset = 66,Token in error = JOIN ]
This is My SQL:
var query = "SELECT Team.TeamName, Fixtures.HomeTeam" +
"FROM Team" +
"LEFT JOIN Fixtures" +
"ON Team.TeamId=Fixtures.HomeTeam" +
"ORDER BY Team.TeamName";
Team Table Has PK: TeamId
Fixture Table Has FK: HomeTeam
I am using WebMatrix 2. Razor WebPages
No spaces between line concatenations. Change every line to include space at the end.
var query = "SELECT Team.TeamName, Fixtures.HomeTeam " +
"FROM Team " +
"LEFT JOIN Fixtures " +
"ON Team.TeamId=Fixtures.HomeTeam " +
"ORDER BY Team.TeamName";
As pointed by Charles Brentana, you have missed the spaces in your SQL command.
Maybe a better solution is to you use a verbatim string literal, i.e. a string created with an # character before the double-quote character, that can span multiple lines:
var query = #"SELECT Team.TeamName, Fixtures.HomeTeam
FROM Team
LEFT JOIN Fixtures
ON Team.TeamId=Fixtures.HomeTeam
ORDER BY Team.TeamName";
You need spaces between your strings.
I avoid this by putting the space as the first character, so it's really obvious when you forget to code it:
var query = "SELECT Team.TeamName, Fixtures.HomeTeam" +
" FROM Team" +
" LEFT JOIN Fixtures" +
" ON Team.TeamId=Fixtures.HomeTeam" +
" ORDER BY Team.TeamName";
If you consistently code this way you'll be able to spot any missing spaces instantly.
I am trying to insert the guestpass type name in table guestpasstypes and at a time it will check the database whether the database has already that name or not by using this statement:
#"INSERT INTO guestpasstypes(guestPasstype_Name)values('" + tbPassType.Text + "') where not exists (select 'guestPasstype_Name' from guestpasstypes where guestPasstype_Name = '" + tbPassType.Text + "')"
but it accepts the duplicate name too, and it does not work. Would anyone please help on this?
For SQL Server it would look like this.
insert into guestpasstypes (guestPasstype_Name)
select 'name1'
where not exists (select *
from guestpasstypes
where guestPasstype_Name = 'name1')
I think it should work for MySQL as well.
If you are on SQL Server 2008 you can use MERGE.
merge guestpasstypes as G
using (select 'name2') as S(Name)
on G.guestPasstype_Name = S.Name
when not matched then
insert (guestPasstype_Name) values (Name);
UPDATE
I think the first option could be applied to your problem like this:
#"INSERT INTO guestpasstypes(guestPasstype_Name) select '" + tbPassType.Text
+ "' where not exists (select * from guestpasstypes where guestPasstype_Name = '"
+ tbPassType.Text + "')"
If you want it to throw an error you can either :
Put a unique index on the column (the easiest and preferred way)
or
Write a stored procedure which returns an error flag. Within the procedure, you first check for a matching value and if one is found, set the error flag and return. Otherwise do the insert as normal.
Try either INSERT IGNORE or INSERT ON DUPLICATE KEY:
INSERT IGNORE INTO `guestpasstypes`(`guestPasstype_Name`) values('" + tbPassType.Text + "');
OR
INSERT INTO `guestpasstypes`(`guestPasstype_Name`)values('" + tbPassType.Text + "') ON DUPLICATE KEY UPDATE `guestPasstype_Name` = `guestPasstype_Name`;