# Equivalent to INSTR(\<string\>, \<string\>) function for virtual graph mapping

**URL:** <https://community.stardog.com/t/equivalent-to-instr-string-string-function-for-virtual-graph-mapping/4511>\
**Category:** Support\
**Created:** [August 1, 2023, 1:42pm UTC](https://community.stardog.com/t/equivalent-to-instr-string-string-function-for-virtual-graph-mapping/4511 "2023-08-01T13:42:15Z")\
**Posts on this page:** 1\
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<div class="post-metadata">

**Author:** ![PaulJackson](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.stardog.com/pauljackson/32/243_2.png) [@PaulJackson](https://community.stardog.com/u/PaulJackson)\
**Post date:** [August 1, 2023, 4:08pm UTC](https://community.stardog.com/t/equivalent-to-instr-string-string-function-for-virtual-graph-mapping/4511/3 "2023-08-01T16:08:09Z")

</div>

If the error you're getting looks something like:

```plaintext
No match found for function signature instr(<CHARACTER>, <CHARACTER>)

```

... then the error is happening because Stardog's SQL parser doesn't know about the `INSTR` function. You can work around this by adding the following to your [virtual graph options](https://docs.stardog.com/virtual-graphs/virtual-graph-configuration#sqlfunctions):

```auto
sql.functions=instr:varchar

```

-Paul

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_[View the full topic](https://community.stardog.com/t/equivalent-to-instr-string-string-function-for-virtual-graph-mapping/4511)._