Maptitude GISDK Help |
Selects records based on an SQL query.
Optional options array introduced in Version 5.0. Show Progress Bar option added in Version 2017.
n_selected = SelectByQuery (string set_name, string operation, string query [, array options])
Argument |
Contents |
set_name |
The name of the selection set |
operation |
The operation to perform, as indicated below |
query |
The SQL query string |
Operation |
Meaning |
several |
Replaces the contents of the selection set |
less |
Removes features from the selection set |
more |
Adds features to the selection set |
subset |
Selects a subset of the selection set |
Option |
Type |
Contents |
Index Limit |
Integer |
The number of records above which a temporary index will not be built. The default behavior of SelectByQuery() is to build an index if it determines that the index will speed up the query. The "Index Limit" option can prevent this by using a value of 0 |
Inclusion |
String |
"Enclosed" or "Intersecting", overriding the current setting; for more information, see SetSelectInclusion() |
Max |
Integer |
Maximum number of records to select |
Display |
Boolean |
"True" or "False" overriding the current setting; for more information, see SetSelectDisplay() |
Auto Redraw |
Boolean |
"True" or "False" overriding the current setting; for more information, see SetSelectAutoRedraw() |
Source And |
String |
A selection set on the current layer that records must be in to be selected |
Source Not |
String |
A selection set on the current layer that records must not be in to be selected |
Show Progress Bar |
Boolean |
"True" to show the progress bar, otherwise "False" |
An integer indicating the number of records in the selection set.
The options array is an optional argument.
All selection commands operate on the current layer or view.
If the set does not already exist, SelectByQuery() creates it.
Queries must be of the form "Select * where condition." Condition must be a valid boolean expression as described in "Formulas, Conditions, and Functions" in the Maptitude Help.
SelectByQuery() displays a progress bar. To add a Cancel button to the progress bar, precede the function call with an "on escape" clause. For more information, see Error Handling.
qry1 = "Select * where Income > 50000"
qry2 = 'Select * where Category = "Retail" '
n1 = SelectByQuery("High Income", "Several", qry1,)
n2 = SelectByQuery("Retail Stores", "Several", qry2, {{"Index Limit", 0}})
Error Type |
Meaning |
Error |
The set name, operation type, or query string is invalid, or the view has not been set |
NotFound |
The value being checked for doesn't exist |
Function |
Summary |
Selects records based on an SQL query that is stored in a file |
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