I'm trying to figure out why this function is ignoring the middle most table? I'm overlooking something simple I assume.
Here's the code
tbl = {
name = "first table";
tbl = {
name = "middle table";
tbl = {
name = "last table";
};
};
}
sayName = function(tbl)
print(tbl.name)
if tbl.tbl ~= nil then
for _,v in pairs(tbl.tbl) do
sayName(v)
end;
end;
end;
sayName(tbl)
Output>
first table
last table
nil
In your example, you have a recursive structure, each table have 1 name and possibly a sub-table named tbl. So, I am not clear why would one use the for loop in these conditions.
tbl = {
name = "first table",
tbl = {
name = "middle table",
tbl = {
name = "last table"
}
}
}
function PrintTable (Table)
print("# Name", Table.name)
local SubTable = Table.tbl
if SubTable then
return PrintTable(SubTable)
end
end
PrintTable(tbl)
Will return:
# Name first table
# Name middle table
# Name last table
Is it possible to create a request in Sqlite3 of the SELECT type, which will contain the condition "select a row where amount NULL (or IS NOT NULL) cells will be more (less) a certain number"?
With this query:
SELECT * FROM tablename
WHERE (col1 IS NULL) + (col2 IS NULL) + (col3 IS NULL) + .... > ?
Each of the expressions (colX IS NULL) or (colX IS NOT NULL) evaluates to 1 for true or 0 for false, so you can compare their sum to the number ? that you want.
Trying to display a users Lastname, Firstname --- Website
And I need to insert a comma and space after Lastname to a GridView.
I am trying to add a CASE statement in SQL and having trouble figuring it out.
Perhaps I need to use #parameter (scalar variable?) to abstract the
memory read from CASE statement; or my syntax is wrong and I just don't
understand.
SELECT
CASE
WHEN IsNull(people_Table.firstName, '') = ''
THEN CONCAT(people_Table.lastName, ', ', people_Table.firstName)
ELSE people_Table.lastName
END as fullName,
people_Table.website
FROM
people_Table
INNER JOIN
membership_Table on people_Table.ID = membership_Table.personID
WHERE
rectype = 'Master'
AND membershipType = 'Business'
AND expirationDate > GetDate()
ORDER BY
people_Table.lastName
Getting SQL Server error:
Msg 208, Level 16, State 1, Line 1
Invalid object name 'people_Table'.
Otherwise I suppose I should use an asp databoundevent in the template.
What is better for performance and security?
SELECT ISNULL(people_Table.lastName + ', ', '')
+ ISNULL(people_Table.firstName , '') as fullName
, people_Table.website
FROM people_Table INNER JOIN membership_Table on people_Table.ID =
membership_Table.personID
WHERE rectype = 'Master'
AND membershipType = 'Business'
AND expirationDate > GetDate()
ORDER BY people_Table.lastName
OR
SELECT COALESCE(people_Table.lastName + ', ', '')
+ COALESCE(people_Table.firstName , '') as fullName
, people_Table.website
FROM people_Table INNER JOIN membership_Table on people_Table.ID =
membership_Table.personID
WHERE rectype = 'Master'
AND membershipType = 'Business'
AND expirationDate > GetDate()
ORDER BY people_Table.lastName
I have some data in an ArrayList and I would like to use that to filter my Linq query using the where clause.
My Linq code below joins two tables and then I filter them using the Where clause. Now I would like to FURTHER filter this query by using the Arraylist as a filter. So the value come from arraylist
I would like the "where" clause to take one more comparison and the value comes from an arraylist:
where rType.Field<string>("ProfSSCMName") == lbProfiles.SelectedValue && rType.Field<string>("Name") == lbHWTypes.SelectedValue && **arrayList.Tostring()**
This is the code that I am using.
Can anyone tell me how can I further filter my Linq query using the values in the arraylist?
joined = from rType in ds.Tables["HWTypes"].AsEnumerable()
join rStock in ds.Tables["Stock"].AsEnumerable()
on rType.Field<string>("ProductID") equals rStock.Field<string>("Partno")
where rType.Field<string>("ProfSSCMName") == lbProfiles.SelectedValue && rType.Field<string>("Name") == lbHWTypes.SelectedValue
select new
{
TagNumber = rStock.Field<string>("TagNumber"),
SerialNumber = rStock.Field<string>("SerialNumber"),
Partno = rStock.Field<string>("Partno"),
PartType = rStock.Field<string>("PartType"),
EcopartSubtype = rStock.Field<string>("EcopartSubtype"),
AzertyQuerty = rStock.Field<string>("Azerty/Querty"),
ProductID = rType.Field<string>("ProductID"),
Name = rType.Field<string>("Name"),
SCCMKeyboard = rType.Field<string>("SCCMKeyboard"),
DisplayName = rType.Field<string>("DisplayName"),
ProfSSCMName = rType.Field<string>("ProfSSCMName"),
TagNameDisplayName = rStock.Field<string>("TagNumber") + " " + rType.Field<string>("DisplayName")
// add the other columns you need here
};
You seem to be using Linq-To-Objects.
So you can just use contains on the arraylist
where rType.Field<string>("ProfSSCMName") == lbProfiles.SelectedValue
&& rType.Field<string>("Name") == lbHWTypes.SelectedValue
&& arrayList.Contains( rType.Field<string>("Name") )
Is it possible to get a row with all column names of a table like this?
|id|foo|bar|age|street|address|
I don't like to use Pragma table_info(bla).
SELECT sql FROM sqlite_master
WHERE tbl_name = 'table_name' AND type = 'table'
Then parse this value with Reg Exp (it's easy) which could looks similar to this: [(.*?)]
Alternatively you can use:
PRAGMA table_info(table_name)
If you are using the command line shell to SQLite then .headers on before you perform your query. You only need to do this once in a given session.
You can use pragma related commands in sqlite like below
pragma table_info("table_name")
--Alternatively
select * from pragma_table_info("table_name")
If you require column names like id|foo|bar|age|street|address, basically your answer is in below query.
select group_concat(name,'|') from pragma_table_info("table_name")
Yes, you can achieve this by using the following commands:
sqlite> .headers on
sqlite> .mode column
The result of a select on your table will then look like:
id foo bar age street address
---------- ---------- ---------- ---------- ---------- ----------
1 val1 val2 val3 val4 val5
2 val6 val7 val8 val9 val10
This helps for HTML5 SQLite:
tx.executeSql('SELECT name, sql FROM sqlite_master WHERE type="table" AND name = "your_table_name";', [], function (tx, results) {
var columnParts = results.rows.item(0).sql.replace(/^[^\(]+\(([^\)]+)\)/g, '$1').split(','); ///// RegEx
var columnNames = [];
for(i in columnParts) {
if(typeof columnParts[i] === 'string')
columnNames.push(columnParts[i].split(" ")[0]);
}
console.log(columnNames);
///// Your code which uses the columnNames;
});
You can reuse the regex in your language to get the column names.
Shorter Alternative:
tx.executeSql('SELECT name, sql FROM sqlite_master WHERE type="table" AND name = "your_table_name";', [], function (tx, results) {
var columnNames = results.rows.item(0).sql.replace(/^[^\(]+\(([^\)]+)\)/g, '$1').replace(/ [^,]+/g, '').split(',');
console.log(columnNames);
///// Your code which uses the columnNames;
});
Use a recursive query. Given
create table t (a int, b int, c int);
Run:
with recursive
a (cid, name) as (select cid, name from pragma_table_info('t')),
b (cid, name) as (
select cid, '|' || name || '|' from a where cid = 0
union all
select a.cid, b.name || a.name || '|' from a join b on a.cid = b.cid + 1
)
select name
from b
order by cid desc
limit 1;
Alternatively, just use group_concat:
select '|' || group_concat(name, '|') || '|' from pragma_table_info('t')
Both yield:
|a|b|c|
The result set of a query in PHP offers a couple of functions allowing just that:
numCols()
columnName(int $column_number )
Example
$db = new SQLIte3('mysqlite.db');
$table = 'mytable';
$tableCol = getColName($db, $table);
for ($i=0; $i<count($tableCol); $i++){
echo "Column $i = ".$tableCol[$i]."\n";
}
function getColName($db, $table){
$qry = "SELECT * FROM $table LIMIT 1";
$result = $db->query($qry);
$nCols = $result->numCols();
for ($i = 0; $i < $ncols; $i++) {
$colName[$i] = $result->columnName($i);
}
return $colName;
}
$<?
$db = sqlite_open('mysqlitedb');
$cols = sqlite_fetch_column_types('form name'$db, SQLITE_ASSOC);
foreach ($cols as $column => $type) {
echo "Column: $column Type: $type\n";
}
Using #Tarkus's answer, here are the regexes I used in R:
getColNames <- function(conn, tableName) {
x <- dbGetQuery( conn, paste0("SELECT sql FROM sqlite_master WHERE tbl_name = '",tableName,"' AND type = 'table'") )[1,1]
x <- str_split(x,"\\n")[[1]][-1]
x <- sub("[()]","",x)
res <- gsub( '"',"",str_extract( x[1], '".+"' ) )
x <- x[-1]
x <- x[-length(x)]
res <- c( res, gsub( "\\t", "", str_extract( x, "\\t[0-9a-zA-Z_]+" ) ) )
res
}
Code is somewhat sloppy, but it appears to work.
Try this sqlite table schema parser, I implemented the sqlite table parser for parsing the table definitions in PHP.
It returns the full definitions (unique, primary key, type, precision, not null, references, table constraints... etc)
https://github.com/maghead/sqlite-parser
Easiest way to get the column names of the most recently executed SELECT is to use the cursor's description property. A Python example:
print_me = "("
for description in cursor.description:
print_me += description[0] + ", "
print(print_me[0:-2] + ')')
# Example output: (inp, output, reason, cond_cnt, loop_likely)