Hi you cannot retrieve the values of the picklist by simply using SOQL query.
Instead you have to make a call on sobject describe using your php server.
eg- I just made request on my SF org for account object
https://***yourInstance***.salesforce.com/services/data/v20.0/sobjects/Account/describe/ -H "Authorization: Bearer token"
and got the raw response in which I have all fields information in json format which you need to parse and get picklist values.
Below is the sample response just to explain where you can see Account Rating is the picklist with three picklist values - Hot, Warm and cold.
{
"activateable" : false,
"childRelationships" : [ {
"cascadeDelete" : false,
"childSObject" : "Account",
"deprecatedAndHidden" : false,
"field" : "ParentId",
"relationshipName" : "ChildAccounts"
}
"feedEnabled" : true,
"fields" : [ {
"autoNumber" : false,
"byteLength" : 18,
"calculated" : false,
"calculatedFormula" : null,
"caseSensitive" : false,
"controllerName" : null,
"createable" : false,
"custom" : false,
"defaultValue" : null,
"defaultValueFormula" : null,
"defaultedOnCreate" : true,
"dependentPicklist" : false,
"deprecatedAndHidden" : false,
"digits" : 0,
"externalId" : false,
"filterable" : true,
"groupable" : true,
"htmlFormatted" : false,
"idLookup" : true,
"inlineHelpText" : null,
"label" : "Account ID",
"length" : 18,
"name" : "Id",
"nameField" : false,
"namePointing" : false,
"nillable" : false,
"picklistValues" : [ ],
"precision" : 0,
"referenceTo" : [ ],
"relationshipName" : null,
"relationshipOrder" : null,
"restrictedPicklist" : false,
"scale" : 0,
"soapType" : "tns:ID",
"sortable" : true,
"type" : "id",
"unique" : false,
"updateable" : false,
"writeRequiresMasterRead" : false
}, {
"autoNumber" : false,
"byteLength" : 120,
"calculated" : false,
"calculatedFormula" : null,
"caseSensitive" : false,
"controllerName" : null,
"createable" : true,
"custom" : false,
"defaultValue" : null,
"defaultValueFormula" : null,
"defaultedOnCreate" : false,
"dependentPicklist" : false,
"deprecatedAndHidden" : false,
"digits" : 0,
"externalId" : false,
"filterable" : true,
"groupable" : true,
"htmlFormatted" : false,
"idLookup" : false,
"inlineHelpText" : null,
"label" : "Account Rating",
"length" : 40,
"name" : "Rating",
"nameField" : false,
"namePointing" : false,
"nillable" : true,
"picklistValues" : [ {
"active" : true,
"defaultValue" : false,
"label" : "Hot",
"validFor" : null,
"value" : "Hot"
}, {
"active" : true,
"defaultValue" : false,
"label" : "Warm",
"validFor" : null,
"value" : "Warm"
}, {
"active" : true,
"defaultValue" : false,
"label" : "Cold",
"validFor" : null,
"value" : "Cold"
} ],
"precision" : 0,
"referenceTo" : [ ],
"relationshipName" : null,
"relationshipOrder" : null,
"restrictedPicklist" : false,
"scale" : 0,
"soapType" : "xsd:string",
"sortable" : true,
"type" : "picklist",
"unique" : false,
"updateable" : true,
"writeRequiresMasterRead" : false
} ],
"replicateable" : true,
"retrieveable" : true,
"searchLayoutable" : null,
"searchable" : true,
"triggerable" : true,
"undeletable" : true,
"updateable" : true,
"urls" : {
"rowTemplate" : "/services/data/v20.0/sobjects/Account/{ID}",
"uiDetailTemplate" : "https://rishilightning-dev-ed.my.salesforce.com/{ID}",
"uiEditTemplate" : "https://rishilightning-dev-ed.my.salesforce.com/{ID}/e",
"describe" : "/services/data/v20.0/sobjects/Account/describe",
"uiNewRecord" : "https://rishilightning-dev-ed.my.salesforce.com/001/e",
"sobject" : "/services/data/v20.0/sobjects/Account"
}
}