# OPC write back (SQL tags)

**URL:** <https://forum.inductiveautomation.com/t/opc-write-back-sql-tags/57179>\
**Category:** Ignition\
**Tags:** ignition79\
**Created:** [March 14, 2022, 8:11pm UTC](https://forum.inductiveautomation.com/t/opc-write-back-sql-tags/57179 "2022-03-14T20:11:40Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sathianandan.dharmas](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@sathianandan.dharmas](https://forum.inductiveautomation.com/u/sathianandan.dharmas)\
**Post date:** [March 14, 2022, 8:11pm UTC](https://forum.inductiveautomation.com/t/opc-write-back-sql-tags/57179/1 "2022-03-14T20:11:40Z")

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Hi All,

I’m not able to write to some OPC tags which are in read/write mode using the OPC write back option on a SQL tag but I’m able to write values using system.opc.writeValue() function though. Does anyone know what could be missing? These write-back options used to work before though, we recently upgraded ignition to 7.9.18 from 7.9.14 so I’m not sure if it has anything to do with it.

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/d/9d2a3912500078b7892925f566280f86421b522d.png)

TIA

Sam

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [March 15, 2022, 12:56am UTC](https://forum.inductiveautomation.com/t/opc-write-back-sql-tags/57179/2 "2022-03-15T00:56:12Z")

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You might need a cast in SQL to the nearest datatype matching that OPC item.