Syntactical error with the use of == instead of = for comparison in the WHERE clause.

[dotsLand]

What is the bug or the crash?

Issue Summary:
On a warning message was generated in QGIS due to an erroneous SQL query. The query attempted to retrieve data from the layer_styles table, but it contained a syntactical error with the use of == instead of = for comparison in the WHERE clause. As a result, the query failed to execute, leading to the reported error.

Error Details:

2023-09-15T00:05:58     WARNING    NOTICE: row number 0 is out of range 0..-1
2023-09-15T09:31:54     WARNING    Erroneous query: SELECT styleName FROM layer_styles WHERE f_table_catalog='knffis32' AND f_table_schema='kca' AND f_table_name='adm_rks_border' AND f_geometry_column=='geom' AND (type='Polygon' OR type IS NULL) AND styleName='Kufijt Administrative' returned 7 [ERROR: operator does not exist: character varying == unknown
             LINE 1: ..._table_name='adm_rks_border' AND f_geometry_column=='geom' A...
              ^
             HINT: No operator matches the given name and argument types. You might need to add explicit type casts.
             ]

Date and Time: [Date and Time]
Error Level: WARNING
Error Message: Erroneous query: SELECT styleName FROM layer_styles WHERE f_table_catalog='knffis32' AND f_table_schema='kca' AND f_table_name='adm_rks_border' AND f_geometry_column=='geom' AND (type='Polygon' OR type IS NULL) AND styleName='Kufijt Administrative' returned 7 [ERROR: operator does not exist: character varying == unknown
LINE 1: ..._table_name='adm_rks_border' AND f_geometry_column=='geom' A...
HINT: No operator matches the given name and argument types. You might need to add explicit type casts.]
Root Cause:
The root cause of this issue is the use of == for comparison in the SQL query, which is not a valid operator in SQL. In SQL, the correct operator for equality comparison is =.

Impact:
The impact of this error is that the SQL query cannot be executed successfully, and it results in a database error. This may lead to incorrect or missing data in QGIS when attempting to retrieve styles for the specified table and geometry column.

Resolution:
To resolve this issue, the SQL query should be modified to use the correct equality operator (=) instead of ==.

Steps to reproduce the issue

1. Save one QGIS Style into Postgresql Database
2. load layer from database in QGIS

Versions

QGIS version
3.28.10-Firenze
QGIS code revision
e2edb9c

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[rouault]

This has been fixed 2 weeks ago per 3ed6e10 and should be available in 3.28.11