| Label | Explanation | Data Type |
Input Tables | The name of the table or tables to be used in the query. If several tables are listed, the Expression parameter can be used to define how they will be joined. The input table can be from a geodatabase or a database connection. | Table View; Raster Layer |
Table Name | The name of the layer or table view that will be created. | Table View; Raster Layer |
Key Field Options | Specifies how an ObjectID field will be generated (if at all) for the query. Layers and table views in ArcGIS require an ObjectID field. An ObjectID field is an integer field that uniquely identifies rows in the data being used. The default is Use key fields (USE_KEY_FIELDS in Python).
| String |
Key Fields (Optional) | A field or combination of fields that will be used to uniquely identify a row in the query. This parameter is used only when the Key Field Options parameter is set to Use Key Fields. | Field |
Fields (Optional) | The fields to include in the layer or table view. If an alias is set for a field, this is the name that appears. If no fields are specified, all fields from all tables are included. If a Shape field is added to the field list, the result is a layer; otherwise it is a table view. | Value Table |
Expression (Optional) | An SQL expression used to select a subset of records. | SQL Expression |
Summary
Applies an SQL query to a database, and the results are represented in either a layer or table view. The query can be used to join several tables or return a subset of fields or rows from the original data in the database.
This tool accepts data from a geodatabase or an OLE DB connection.
Usage
The layer that is created by the tool is temporary and will not persist after the session ends unless the document is saved.
All input feature classes or tables must be from the same input workspace.
If a Shape field is added to the field list, the result is a layer; otherwise, it is a table view.
If the output result is a layer, it can be persisted to a layer file using the Save To Layer File tool or to a feature class using the Copy Features tool.
The order of the fields in the field list is the order the fields will appear in the output layer or table view.
The tool allows you to provide a key field option and key fields list. This information defines how rows are uniquely identified and is used to add a dynamically generated ObjectID field to the data. Without an ObjectID field, selections will not be supported.
You can choose several fields from the key fields list if the combination of these fields is needed to define unique values.
If an SQL expression is used but returns no matching records, the output feature class will be empty.
Feature classes can be joined, but the fields list must contain at most one field of type geometry.
For details on the syntax for the Expression parameter, see SQL mode.
When input tables are from a file geodatabase, tables generally join in the order listed in the Input Tables parameter. For example, if Table1 is listed before Table2, Table2 will be joined by getting a row from Table1, then getting matching rows from Table2. However, if this would result in querying Table2 on a nonindexed field, and reversing the order would result in querying Table1 on an indexed field, the order will be reversed in an attempt to maximize performance. This is the sole query optimization logic at work when you're using file geodatabase data with this tool. In general, joins in file geodatabases perform best when they are one-to-many or one-to-one.
Parameters
arcpy.management.MakeQueryTable(in_table, out_table, in_key_field_option, {in_key_field}, {in_field}, {where_clause})| Name | Explanation | Data Type |
in_table [in_table,...] | The name of the table or tables to be used in the query. If several tables are listed, the where_clause parameter can be used to define how they will be joined. The input table can be from a geodatabase or a database connection. | Table View; Raster Layer |
out_table | The name of the layer or table view that will be created. | Table View; Raster Layer |
in_key_field_option | Specifies how an ObjectID field will be generated (if at all) for the query. Layers and table views in ArcGIS require an ObjectID field. An ObjectID field is an integer field that uniquely identifies rows in the data being used. The default is Use key fields (USE_KEY_FIELDS in Python).
| String |
in_key_field [in_key_field,...] (Optional) | A field or combination of fields that will be used to uniquely identify a row in the query. This parameter is used only when in_key_field_option = "USE_KEY_FIELDS". | Field |
in_field [[field, {alias}],...] (Optional) | The fields to include in the layer or table view. If an alias is set for a field, this is the name that appears. If no fields are specified, all fields from all tables are included. If a Shape field is added to the field list, the result is a layer; otherwise it is a table view. | Value Table |
where_clause (Optional) | An SQL expression used to select a subset of records. | SQL Expression |
Code sample
The following Python window script demonstrates how to use the MakeQueryTable function in immediate mode.
import arcpy
arcpy.env.workspace = "C:/data/data.gdb"
arcpy.MakeQueryTable_management(["Counties","codemog"], "queryout", "ADD_VIRTUAL_KEY_FIELD", "",
[["Counties.OBJECTID", 'ObjectID'], ["Counties.NAME", 'Name'],
["codemog.Males", 'Males'], ["codemog.Females", 'Females']],
"Counties.FIPS = codemog.Fips and Counties.STATE_NAME = 'California'")The following script is an example of how to use the MakeQueryTable tool in the Python scripting environment.
# MakeQueryTableOLEDB.py
# Description: Create a query table from two OLE DB tables using a limited set of
# fields and establishing an equal join.
# Import system modules
import arcpy
# Local variables...
tableList = ["c:/Connections/balrog.odc/vtest.COUNTIES",\
"c:/Connections/balrog.odc/vtest.CODEMOG"]
fieldList = [["vtest.COUNTIES.OBJECTID", 'ObjectID'], ["vtest.COUNTIES.NAME", 'Name']\
["vtest.CODEMOG.Males", 'Males'], ["vtest.CODEMOG.Females", 'Females']]
whereClause = "vtest.COUNTIES.FIPS = vtest.CODEMOG.Fips" +\
"and vtest.COUNTIES.STATE_NAME = 'California'"
keyField = "vtest.COUNTIES.OBJECTID"
lyrName = "CountyCombined"
# Make Query Table...
arcpy.MakeQueryTable_management(tableList, lyrName,"USE_KEY_FIELDS", keyField, fieldList, whereClause)
# Print the total rows
print(arcpy.GetCount_management(lyrName))
# Print the fields
fields = arcpy.ListFields(lyrName)
for field in fields:
print(field.name)
# Save as a dBASE file
arcpy.CopyRows_management(lyrName, "C:/temp/calinfo.dbf")Environments
Licensing information
- Basic: Yes
- Standard: Yes
- Advanced: Yes