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new 9012ba895c Update filterrows.adoc
new e73cca35ae Merge pull request #3250 from Mattang-Dan/patch-24
9012ba895c is described below
commit 9012ba895c46f941ee7eab3e5d66c2ae1baf1f4c
Author: Mattang-Dan <[email protected]>
AuthorDate: Fri Sep 22 11:45:06 2023 -0400
Update filterrows.adoc
Update filterrows.adoc
---
.../ROOT/pages/pipeline/transforms/filterrows.adoc | 25 ++++++++++++++++------
1 file changed, 18 insertions(+), 7 deletions(-)
diff --git
a/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/filterrows.adoc
b/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/filterrows.adoc
index f682c42aed..c085c71e54 100644
---
a/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/filterrows.adoc
+++
b/docs/hop-user-manual/modules/ROOT/pages/pipeline/transforms/filterrows.adoc
@@ -56,9 +56,12 @@ TIP: Lists also works on numeric values like integers. In
this case, the list of
|Send 'true' data to transform|The rows for which the condition specified is
true are sent to this transform
|Send 'false' data to transform|The rows for which the condition specified are
false are sent to this transform
|The Condition|
-|Add Condition| Click to add conditions.
-Add condition converts the original condition into a sub-level condition.
-Click a sub-condition to edit it by going down one level in the condition tree.
+|Add Condition| Click to add conditions. Add condition converts the original
condition into a sub-level condition.
+
+* Click a sub-condition to edit it by going down one level in the condition
tree.
+
+* Right-click a condition to edit, delete, move, or add a sub-condition.
+
|===
== Filtering
@@ -66,12 +69,15 @@ Click a sub-condition to edit it by going down one level in
the condition tree.
=== Filtering rows based on values from variables
The filter rows transform detects only fields in the input stream.
-If you want to filter rows based on a variable value, you must modify the
previous transform (a table input for example) and include the variable as
another field, for example:
-[source,bash]
+The filter rows transform detects only fields in the input stream. If you want
to filter rows based on a variable value, you can modify the previous
transform. For example, a table input transform can include the variable in the
SQL as another field such as
+[source,sql]
----
-${myvar}=5
+SELECT field1, field2, ${myvar} AS field3 FROM table1
----
+, then in the filter row condition you can say field1 = field3. Alternatively,
you can use a ‘Get Variables’ transform to set parameters in fields.
+
+You can use a REGEX expression in the "filter row" transform.
A query:
@@ -93,6 +99,9 @@ field1 = field3
*FYI* - instead of the Table Input trick above you can use the simple "Get
Variables" transform to set parameters in fields.
+Remember that all transforms are executed in parallel, so both true and false
paths will run in some cases.
+In some cases it will be better to use a where filter in a SQL query than use
a Filter rows transform. If you need to return input rows for either case
(true/false), you can use various SQL query methods that will always return
results using IF EXISTS or IS NULL for example.
+
=== Filtering special characters
To filter special characters like explicit EOF (e.g. from old cobol files) Use
a REGEX expression in the "filter row" transform with the syntax:
"\x{openvar}1A{closevar}" where \x mean HEX representation and 1A into
parenthesis is the EOF char to match in HEX.
@@ -102,6 +111,8 @@ To filter special characters like explicit EOF (e.g. from
old cobol files) Use a
All fields of this transform support metadata injection.
You can use this transform with ETL Metadata Injection to pass metadata to
your pipeline at runtime.
+If you cannot select the field you would like because it does not exist yet
because of metadata injection, see this doc:
https://hop.apache.org//manual/latest/pipeline/transforms/filterrows.html#_mdi_example
and this example in the samples project:
metadata-injection/filter-rows-mdi-parent.hpl
+
== Special considerations for the condition field
The Filter Rows transform is a special MDI scenario, since it has a nested
structure of filter conditions.
@@ -168,4 +179,4 @@ housenr > 100
</condition>
</conditions>
</condition>
-----
\ No newline at end of file
+----
