Database error due to broken query in RestoreBackgroundImageColor

[nickvergessen]

server/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php

Line 72 in 9836e9b

->leftJoin('a', $qb->createFunction('(' . $innerSQL->getSQL() . ')'), 'b', 'a.userid = b.userid')

Details

{
  "reqId": "SM9jXzWB5PaQ7Lz9GkRO",
  "level": 3,
  "time": "2025-09-19T06:25:07+00:00",
  "remoteAddr": "",
  "user": "--",
  "app": "core",
  "method": "",
  "url": "--",
  "message": "Error while running background job OCA\\Theming\\Jobs\\RestoreBackgroundImageColor (id: 10584862, arguments: {\"stage\":\"prepare\"})",
  "userAgent": "--",
  "version": "33.0.0.0",
  "exception": {
    "Exception": "OC\\DB\\Exceptions\\DbalException",
    "Message": "An exception occurred while executing a query: SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near \"\" FROM \"\"\nLINE 1: ...\"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc...\n                                                             ^",
    "Code": 7,
    "Trace": [
      {
        "file": "/var/www/html/lib/private/DB/ConnectionAdapter.php",
        "line": 53,
        "function": "wrap",
        "class": "OC\\DB\\Exceptions\\DbalException",
        "type": "::",
        "args": [
          {
            "__class__": "Doctrine\\DBAL\\Exception\\SyntaxErrorException"
          },
          "",
          "SELECT DISTINCT `a`.`userid` FROM `*PREFIX*preferences` `a` LEFT JOIN `*PREFIX*(SELECT `userid` FROM `*PREFIX*preferences` WHERE `configkey` = :dcValue1)` `b` ON a.userid = b.userid WHERE (`a`.`configkey` = :dcValue2) AND (`a`.`configvalue` <> :dcValue3) AND (`b`.`userid` IS NULL)"
        ]
      },
      {
        "file": "/var/www/html/lib/private/DB/QueryBuilder/QueryBuilder.php",
        "line": 291,
        "function": "executeQuery",
        "class": "OC\\DB\\ConnectionAdapter",
        "type": "->",
        "args": [
          "SELECT DISTINCT `a`.`userid` FROM `*PREFIX*preferences` `a` LEFT JOIN `*PREFIX*(SELECT `userid` FROM `*PREFIX*preferences` WHERE `configkey` = :dcValue1)` `b` ON a.userid = b.userid WHERE (`a`.`configkey` = :dcValue2) AND (`a`.`configvalue` <> :dcValue3) AND (`b`.`userid` IS NULL)",
          {
            "dcValue1": "background_color",
            "dcValue2": "background_image",
            "dcValue3": "default"
          },
          {
            "dcValue1": 2,
            "dcValue2": 2,
            "dcValue3": 2
          }
        ]
      },
      {
        "file": "/var/www/html/lib/private/DB/QueryBuilder/ExtendedQueryBuilder.php",
        "line": 285,
        "function": "executeQuery",
        "class": "OC\\DB\\QueryBuilder\\QueryBuilder",
        "type": "->",
        "args": [
          {
            "__class__": "OC\\DB\\ConnectionAdapter"
          }
        ]
      },
      {
        "file": "/var/www/html/lib/private/DB/QueryBuilder/Sharded/ShardedQueryBuilder.php",
        "line": 361,
        "function": "executeQuery",
        "class": "OC\\DB\\QueryBuilder\\ExtendedQueryBuilder",
        "type": "->",
        "args": [
          null
        ]
      },
      {
        "file": "/var/www/html/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php",
        "line": 424,
        "function": "executeQuery",
        "class": "OC\\DB\\QueryBuilder\\Sharded\\ShardedQueryBuilder",
        "type": "->",
        "args": [
          null
        ]
      },
      {
        "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
        "line": 76,
        "function": "executeQuery",
        "class": "OC\\DB\\QueryBuilder\\Partitioned\\PartitionedQueryBuilder",
        "type": "->",
        "args": []
      },
      {
        "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
        "line": 50,
        "function": "runPreparation",
        "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
        "type": "->",
        "args": []
      },
      {
        "file": "/var/www/html/lib/public/BackgroundJob/Job.php",
        "line": 49,
        "function": "run",
        "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
        "type": "->",
        "args": [
          {
            "stage": "prepare"
          }
        ]
      },
      {
        "file": "/var/www/html/lib/public/BackgroundJob/QueuedJob.php",
        "line": 30,
        "function": "start",
        "class": "OCP\\BackgroundJob\\Job",
        "type": "->",
        "args": [
          {
            "__class__": "OC\\BackgroundJob\\JobList"
          }
        ]
      },
      {
        "file": "/var/www/html/cron.php",
        "line": 174,
        "function": "start",
        "class": "OCP\\BackgroundJob\\QueuedJob",
        "type": "->",
        "args": [
          {
            "__class__": "OC\\BackgroundJob\\JobList"
          }
        ]
      }
    ],
    "File": "/var/www/html/lib/private/DB/Exceptions/DbalException.php",
    "Line": 56,
    "Previous": {
      "Exception": "Doctrine\\DBAL\\Exception\\SyntaxErrorException",
      "Message": "An exception occurred while executing a query: SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near \"\" FROM \"\"\nLINE 1: ...\"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc...\n                                                             ^",
      "Code": 7,
      "Trace": [
        {
          "file": "/var/www/html/3rdparty/doctrine/dbal/src/Connection.php",
          "line": 1976,
          "function": "convert",
          "class": "Doctrine\\DBAL\\Driver\\API\\PostgreSQL\\ExceptionConverter",
          "type": "->",
          "args": [
            {
              "__class__": "Doctrine\\DBAL\\Driver\\PDO\\Exception"
            },
            {
              "__class__": "Doctrine\\DBAL\\Query"
            }
          ]
        },
        {
          "file": "/var/www/html/3rdparty/doctrine/dbal/src/Connection.php",
          "line": 1918,
          "function": "handleDriverException",
          "class": "Doctrine\\DBAL\\Connection",
          "type": "->",
          "args": [
            {
              "__class__": "Doctrine\\DBAL\\Driver\\PDO\\Exception"
            },
            {
              "__class__": "Doctrine\\DBAL\\Query"
            }
          ]
        },
        {
          "file": "/var/www/html/3rdparty/doctrine/dbal/src/Connection.php",
          "line": 1111,
          "function": "convertExceptionDuringQuery",
          "class": "Doctrine\\DBAL\\Connection",
          "type": "->",
          "args": [
            {
              "__class__": "Doctrine\\DBAL\\Driver\\PDO\\Exception"
            },
            "SELECT DISTINCT \"a\".\"userid\" FROM \"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc_preferences\" WHERE \"configkey\" = :dcValue1)\" \"b\" ON a.userid = b.userid WHERE (\"a\".\"configkey\" = ?) AND (\"a\".\"configvalue\" <> ?) AND (\"b\".\"userid\" IS NULL)",
            [
              "background_image",
              "default"
            ],
            [
              2,
              2
            ]
          ]
        },
        {
          "file": "/var/www/html/lib/private/DB/Connection.php",
          "line": 420,
          "function": "executeQuery",
          "class": "Doctrine\\DBAL\\Connection",
          "type": "->",
          "args": [
            "SELECT DISTINCT \"a\".\"userid\" FROM \"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc_preferences\" WHERE \"configkey\" = :dcValue1)\" \"b\" ON a.userid = b.userid WHERE (\"a\".\"configkey\" = ?) AND (\"a\".\"configvalue\" <> ?) AND (\"b\".\"userid\" IS NULL)",
            [
              "background_image",
              "default"
            ],
            [
              2,
              2
            ],
            null
          ]
        },
        {
          "file": "/var/www/html/lib/private/DB/ConnectionAdapter.php",
          "line": 50,
          "function": "executeQuery",
          "class": "OC\\DB\\Connection",
          "type": "->",
          "args": [
            "SELECT DISTINCT \"a\".\"userid\" FROM \"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc_preferences\" WHERE \"configkey\" = :dcValue1)\" \"b\" ON a.userid = b.userid WHERE (\"a\".\"configkey\" = :dcValue2) AND (\"a\".\"configvalue\" <> :dcValue3) AND (\"b\".\"userid\" IS NULL)",
            {
              "dcValue1": "background_color",
              "dcValue2": "background_image",
              "dcValue3": "default"
            },
            {
              "dcValue1": 2,
              "dcValue2": 2,
              "dcValue3": 2
            }
          ]
        },
        {
          "file": "/var/www/html/lib/private/DB/QueryBuilder/QueryBuilder.php",
          "line": 291,
          "function": "executeQuery",
          "class": "OC\\DB\\ConnectionAdapter",
          "type": "->",
          "args": [
            "SELECT DISTINCT `a`.`userid` FROM `*PREFIX*preferences` `a` LEFT JOIN `*PREFIX*(SELECT `userid` FROM `*PREFIX*preferences` WHERE `configkey` = :dcValue1)` `b` ON a.userid = b.userid WHERE (`a`.`configkey` = :dcValue2) AND (`a`.`configvalue` <> :dcValue3) AND (`b`.`userid` IS NULL)",
            {
              "dcValue1": "background_color",
              "dcValue2": "background_image",
              "dcValue3": "default"
            },
            {
              "dcValue1": 2,
              "dcValue2": 2,
              "dcValue3": 2
            }
          ]
        },
        {
          "file": "/var/www/html/lib/private/DB/QueryBuilder/ExtendedQueryBuilder.php",
          "line": 285,
          "function": "executeQuery",
          "class": "OC\\DB\\QueryBuilder\\QueryBuilder",
          "type": "->",
          "args": [
            {
              "__class__": "OC\\DB\\ConnectionAdapter"
            }
          ]
        },
        {
          "file": "/var/www/html/lib/private/DB/QueryBuilder/Sharded/ShardedQueryBuilder.php",
          "line": 361,
          "function": "executeQuery",
          "class": "OC\\DB\\QueryBuilder\\ExtendedQueryBuilder",
          "type": "->",
          "args": [
            null
          ]
        },
        {
          "file": "/var/www/html/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php",
          "line": 424,
          "function": "executeQuery",
          "class": "OC\\DB\\QueryBuilder\\Sharded\\ShardedQueryBuilder",
          "type": "->",
          "args": [
            null
          ]
        },
        {
          "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
          "line": 76,
          "function": "executeQuery",
          "class": "OC\\DB\\QueryBuilder\\Partitioned\\PartitionedQueryBuilder",
          "type": "->",
          "args": []
        },
        {
          "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
          "line": 50,
          "function": "runPreparation",
          "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
          "type": "->",
          "args": []
        },
        {
          "file": "/var/www/html/lib/public/BackgroundJob/Job.php",
          "line": 49,
          "function": "run",
          "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
          "type": "->",
          "args": [
            {
              "stage": "prepare"
            }
          ]
        },
        {
          "file": "/var/www/html/lib/public/BackgroundJob/QueuedJob.php",
          "line": 30,
          "function": "start",
          "class": "OCP\\BackgroundJob\\Job",
          "type": "->",
          "args": [
            {
              "__class__": "OC\\BackgroundJob\\JobList"
            }
          ]
        },
        {
          "file": "/var/www/html/cron.php",
          "line": 174,
          "function": "start",
          "class": "OCP\\BackgroundJob\\QueuedJob",
          "type": "->",
          "args": [
            {
              "__class__": "OC\\BackgroundJob\\JobList"
            }
          ]
        }
      ],
      "File": "/var/www/html/3rdparty/doctrine/dbal/src/Driver/API/PostgreSQL/ExceptionConverter.php",
      "Line": 62,
      "Previous": {
        "Exception": "Doctrine\\DBAL\\Driver\\PDO\\Exception",
        "Message": "SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near \"\" FROM \"\"\nLINE 1: ...\"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc...\n                                                             ^",
        "Code": 7,
        "Trace": [
          {
            "file": "/var/www/html/3rdparty/doctrine/dbal/src/Driver/PDO/Statement.php",
            "line": 132,
            "function": "new",
            "class": "Doctrine\\DBAL\\Driver\\PDO\\Exception",
            "type": "::",
            "args": [
              {
                "__class__": "PDOException",
                "errorInfo": [
                  "42601",
                  7,
                  "ERROR:  syntax error at or near \"\" FROM \"\"\nLINE 1: ...\"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc...\n                                                             ^"
                ]
              }
            ]
          },
          {
            "file": "/var/www/html/3rdparty/doctrine/dbal/src/Connection.php",
            "line": 1104,
            "function": "execute",
            "class": "Doctrine\\DBAL\\Driver\\PDO\\Statement",
            "type": "->",
            "args": []
          },
          {
            "file": "/var/www/html/lib/private/DB/Connection.php",
            "line": 420,
            "function": "executeQuery",
            "class": "Doctrine\\DBAL\\Connection",
            "type": "->",
            "args": [
              "SELECT DISTINCT \"a\".\"userid\" FROM \"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc_preferences\" WHERE \"configkey\" = :dcValue1)\" \"b\" ON a.userid = b.userid WHERE (\"a\".\"configkey\" = ?) AND (\"a\".\"configvalue\" <> ?) AND (\"b\".\"userid\" IS NULL)",
              [
                "background_image",
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              ],
              [
                2,
                2
              ],
              null
            ]
          },
          {
            "file": "/var/www/html/lib/private/DB/ConnectionAdapter.php",
            "line": 50,
            "function": "executeQuery",
            "class": "OC\\DB\\Connection",
            "type": "->",
            "args": [
              "SELECT DISTINCT \"a\".\"userid\" FROM \"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc_preferences\" WHERE \"configkey\" = :dcValue1)\" \"b\" ON a.userid = b.userid WHERE (\"a\".\"configkey\" = :dcValue2) AND (\"a\".\"configvalue\" <> :dcValue3) AND (\"b\".\"userid\" IS NULL)",
              {
                "dcValue1": "background_color",
                "dcValue2": "background_image",
                "dcValue3": "default"
              },
              {
                "dcValue1": 2,
                "dcValue2": 2,
                "dcValue3": 2
              }
            ]
          },
          {
            "file": "/var/www/html/lib/private/DB/QueryBuilder/QueryBuilder.php",
            "line": 291,
            "function": "executeQuery",
            "class": "OC\\DB\\ConnectionAdapter",
            "type": "->",
            "args": [
              "SELECT DISTINCT `a`.`userid` FROM `*PREFIX*preferences` `a` LEFT JOIN `*PREFIX*(SELECT `userid` FROM `*PREFIX*preferences` WHERE `configkey` = :dcValue1)` `b` ON a.userid = b.userid WHERE (`a`.`configkey` = :dcValue2) AND (`a`.`configvalue` <> :dcValue3) AND (`b`.`userid` IS NULL)",
              {
                "dcValue1": "background_color",
                "dcValue2": "background_image",
                "dcValue3": "default"
              },
              {
                "dcValue1": 2,
                "dcValue2": 2,
                "dcValue3": 2
              }
            ]
          },
          {
            "file": "/var/www/html/lib/private/DB/QueryBuilder/ExtendedQueryBuilder.php",
            "line": 285,
            "function": "executeQuery",
            "class": "OC\\DB\\QueryBuilder\\QueryBuilder",
            "type": "->",
            "args": [
              {
                "__class__": "OC\\DB\\ConnectionAdapter"
              }
            ]
          },
          {
            "file": "/var/www/html/lib/private/DB/QueryBuilder/Sharded/ShardedQueryBuilder.php",
            "line": 361,
            "function": "executeQuery",
            "class": "OC\\DB\\QueryBuilder\\ExtendedQueryBuilder",
            "type": "->",
            "args": [
              null
            ]
          },
          {
            "file": "/var/www/html/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php",
            "line": 424,
            "function": "executeQuery",
            "class": "OC\\DB\\QueryBuilder\\Sharded\\ShardedQueryBuilder",
            "type": "->",
            "args": [
              null
            ]
          },
          {
            "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
            "line": 76,
            "function": "executeQuery",
            "class": "OC\\DB\\QueryBuilder\\Partitioned\\PartitionedQueryBuilder",
            "type": "->",
            "args": []
          },
          {
            "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
            "line": 50,
            "function": "runPreparation",
            "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
            "type": "->",
            "args": []
          },
          {
            "file": "/var/www/html/lib/public/BackgroundJob/Job.php",
            "line": 49,
            "function": "run",
            "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
            "type": "->",
            "args": [
              {
                "stage": "prepare"
              }
            ]
          },
          {
            "file": "/var/www/html/lib/public/BackgroundJob/QueuedJob.php",
            "line": 30,
            "function": "start",
            "class": "OCP\\BackgroundJob\\Job",
            "type": "->",
            "args": [
              {
                "__class__": "OC\\BackgroundJob\\JobList"
              }
            ]
          },
          {
            "file": "/var/www/html/cron.php",
            "line": 174,
            "function": "start",
            "class": "OCP\\BackgroundJob\\QueuedJob",
            "type": "->",
            "args": [
              {
                "__class__": "OC\\BackgroundJob\\JobList"
              }
            ]
          }
        ],
        "File": "/var/www/html/3rdparty/doctrine/dbal/src/Driver/PDO/Exception.php",
        "Line": 24,
        "Previous": {
          "Exception": "PDOException",
          "Message": "SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near \"\" FROM \"\"\nLINE 1: ...\"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc...\n                                                             ^",
          "Code": "42601",
          "Trace": [
            {
              "file": "/var/www/html/3rdparty/doctrine/dbal/src/Driver/PDO/Statement.php",
              "line": 130,
              "function": "execute",
              "class": "PDOStatement",
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              "args": [
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              ]
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            {
              "file": "/var/www/html/3rdparty/doctrine/dbal/src/Connection.php",
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            {
              "file": "/var/www/html/lib/private/DB/Connection.php",
              "line": 420,
              "function": "executeQuery",
              "class": "Doctrine\\DBAL\\Connection",
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              "args": [
                "SELECT DISTINCT \"a\".\"userid\" FROM \"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc_preferences\" WHERE \"configkey\" = :dcValue1)\" \"b\" ON a.userid = b.userid WHERE (\"a\".\"configkey\" = ?) AND (\"a\".\"configvalue\" <> ?) AND (\"b\".\"userid\" IS NULL)",
                [
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                [
                  2,
                  2
                ],
                null
              ]
            },
            {
              "file": "/var/www/html/lib/private/DB/ConnectionAdapter.php",
              "line": 50,
              "function": "executeQuery",
              "class": "OC\\DB\\Connection",
              "type": "->",
              "args": [
                "SELECT DISTINCT \"a\".\"userid\" FROM \"oc_preferences\" \"a\" LEFT JOIN \"oc_(SELECT \"userid\" FROM \"oc_preferences\" WHERE \"configkey\" = :dcValue1)\" \"b\" ON a.userid = b.userid WHERE (\"a\".\"configkey\" = :dcValue2) AND (\"a\".\"configvalue\" <> :dcValue3) AND (\"b\".\"userid\" IS NULL)",
                {
                  "dcValue1": "background_color",
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                }
              ]
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            {
              "file": "/var/www/html/lib/private/DB/QueryBuilder/QueryBuilder.php",
              "line": 291,
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              "class": "OC\\DB\\ConnectionAdapter",
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              "args": [
                "SELECT DISTINCT `a`.`userid` FROM `*PREFIX*preferences` `a` LEFT JOIN `*PREFIX*(SELECT `userid` FROM `*PREFIX*preferences` WHERE `configkey` = :dcValue1)` `b` ON a.userid = b.userid WHERE (`a`.`configkey` = :dcValue2) AND (`a`.`configvalue` <> :dcValue3) AND (`b`.`userid` IS NULL)",
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                },
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                  "dcValue3": 2
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              ]
            },
            {
              "file": "/var/www/html/lib/private/DB/QueryBuilder/ExtendedQueryBuilder.php",
              "line": 285,
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            {
              "file": "/var/www/html/lib/private/DB/QueryBuilder/Sharded/ShardedQueryBuilder.php",
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              "function": "executeQuery",
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              "type": "->",
              "args": [
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            {
              "file": "/var/www/html/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php",
              "line": 424,
              "function": "executeQuery",
              "class": "OC\\DB\\QueryBuilder\\Sharded\\ShardedQueryBuilder",
              "type": "->",
              "args": [
                null
              ]
            },
            {
              "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
              "line": 76,
              "function": "executeQuery",
              "class": "OC\\DB\\QueryBuilder\\Partitioned\\PartitionedQueryBuilder",
              "type": "->",
              "args": []
            },
            {
              "file": "/var/www/html/apps/theming/lib/Jobs/RestoreBackgroundImageColor.php",
              "line": 50,
              "function": "runPreparation",
              "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
              "type": "->",
              "args": []
            },
            {
              "file": "/var/www/html/lib/public/BackgroundJob/Job.php",
              "line": 49,
              "function": "run",
              "class": "OCA\\Theming\\Jobs\\RestoreBackgroundImageColor",
              "type": "->",
              "args": [
                {
                  "stage": "prepare"
                }
              ]
            },
            {
              "file": "/var/www/html/lib/public/BackgroundJob/QueuedJob.php",
              "line": 30,
              "function": "start",
              "class": "OCP\\BackgroundJob\\Job",
              "type": "->",
              "args": [
                {
                  "__class__": "OC\\BackgroundJob\\JobList"
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            },
            {
              "file": "/var/www/html/cron.php",
              "line": 174,
              "function": "start",
              "class": "OCP\\BackgroundJob\\QueuedJob",
              "type": "->",
              "args": [
                {
                  "__class__": "OC\\BackgroundJob\\JobList"
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          ],
          "File": "/var/www/html/3rdparty/doctrine/dbal/src/Driver/PDO/Statement.php",
          "Line": 130
        }
      }
    },
    "message": "Error while running background job OCA\\Theming\\Jobs\\RestoreBackgroundImageColor (id: 10584862, arguments: {\"stage\":\"prepare\"})",
    "exception": {
      "query": "SELECT DISTINCT `a`.`userid` FROM `*PREFIX*preferences` `a` LEFT JOIN `*PREFIX*(SELECT `userid` FROM `*PREFIX*preferences` WHERE `configkey` = :dcValue1)` `b` ON a.userid = b.userid WHERE (`a`.`configkey` = :dcValue2) AND (`a`.`configvalue` <> :dcValue3) AND (`b`.`userid` IS NULL)"
    },
    "CustomMessage": "Error while running background job OCA\\Theming\\Jobs\\RestoreBackgroundImageColor (id: 10584862, arguments: {\"stage\":\"prepare\"})"
  },
  "id": "68ccf7f981523"
}

At least with postgres it errors, but looking at the query in line 29 already shows it's can't work anywhere if executed like this.

The problem seems to origin from

server/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php

Lines 207 to 209 in 5981b7e

	public function leftJoin($fromAlias, $join, $alias, $condition = null): self {
	return $this->join($fromAlias, (string)$join, $alias, $condition, PartitionQuery::JOIN_MODE_LEFT);
	}

which casts the $join to a string and then query builders exceptional handling for IQueryFunctions does not work anymore:

server/lib/private/DB/QueryBuilder/QueryBuilder.php

Lines 1333 to 1335 in 5ecd3c4

	if ($table instanceof IQueryFunction) {
	return (string)$table;
	}

2 confusing things here:

1. It seems the cast was done to allow sub queries while it breaks them: 027fc05
2. The change was only done for left joins, while inner, right and normal join are unchanged.

cc @icewind1991 @susnux