EQL deep dive

Entity Query Language — PFM's query language for filtering records. EQL is parsed into an AST, compiled into parameterised SQL, and can also be evaluated in-memory for Business Rules.

EQL syntax

field=value^ORfield2!=value2^field3>=100^NQfield4ISEMPTY

Symbol	Meaning
`^`	AND — both conditions must match
`^OR`	OR within a group
`^NQ`	New Query — opens a top-level OR group
`^!`	NOT — negates the next condition

Maximum 20 conditions per query.

Operators reference

Operator	Aliases	Type	Example
`=`	`:`	Comparison	`status:open`
`!=`		Comparison	`priority!=low`
`>`	`GT`	Comparison	`amount>100`
`>=`	`GTE`	Comparison	`total>=50`
`<`	`LT`	Comparison	`days<30`
`<=`	`LTE`	Comparison	`score<=80`
`STARTSWITH`	`~^`	Text	`nameSTARTSWITHJohn`
`ENDSWITH`	`~$`	Text	`[email protected]`
`CONTAINS`	`~=`	Text	`descriptionCONTAINSurgent`
`ISEMPTY`		Null	`resolutionISEMPTY`
`ISNOTEMPTY`		Null	`assigned_toISNOTEMPTY`
`IN`		List	`statusINopen,pending`
`NOTIN`		List	`typeNOTINspam,trash`
`BETWEEN`		Range	`amountBETWEEN100,500`
`RELATIVE_GT`		Date	`created_atRELATIVE_GT-7d`
`RELATIVE_LT`		Date	`due_dateRELATIVE_LT+1M`
`SAMEAS`		Field	`shipping_citySAMEASbilling_city`

Business Rules operators

Only available inside Business Rule EQL filters:

Operator	Description
`CHANGES`	True if a field's value changed (pre-save vs post-save)
`DIDNOTCHANGE`	True if a field's value did NOT change

Special value tokens

Token	Resolves to
`CURRENT_USER` / `CURRENT.USER` / `current_user()`	Current WordPress user ID
`TRUE` / `FALSE`	1 / 0
`EMPTY`	Empty string

Where EQL is evaluated

EQL is parsed once and then run in two modes:

Against the database — for list views and REST queries, EQL compiles to a parameterised SQL WHERE clause. SQL injection is impossible by construction; values are always parameter-bound.
In memory against a record — for Business Rules that need to look at CHANGES / DIDNOTCHANGE between pre-save and post-save values, EQL is evaluated against the in-flight record without touching the database.