how to get SqlQueryModel row count if the sql contains table join

To get the row count of a SqlQueryModel that contains a table join, you can use the following code:

# create a QSqlQuery object from the SqlQueryModel
query = model.query()

# build the SQL query
sql = query.lastQuery()

# add the row count to the SQL query
sql += ";\nSELECT COUNT(*) FROM (" + sql + ") AS subquery"

# execute the query and get the row count
query.exec_(sql)
query.next()
row_count = query.value(0)

This code first creates a QSqlQuery object from the SqlQueryModel using the query() method. It then gets the SQL query for the model using the lastQuery() method.

Next, it modifies the SQL query to add a subquery that counts the number of rows returned by the original query. This is done by appending a semicolon, a newline character, and a SELECT COUNT(*) statement to the end of the query.

Finally, it executes the modified SQL query using the exec_() method and retrieves the row count from the first column of the first row using the value() method.

Note that this code assumes that the SqlQueryModel has already been populated with data from the database. If the model has not been populated yet, you will need to call the setQuery() method with the SQL query before calling query() and lastQuery().