动态循环 SQL 列

Question

I'm trying to update table1 from a copy, table2 given a list of columns.

How do I write a sql command to dynamically update all columns in table1 from table2 given a list of column names?.

I'm trying to avoid hardcoding column1, column2 in the sql query.

column_names = ['column1', 'column2'] 
# Want to make query below work automatically
# if I add another column name to `column_names`
sql_cmd = ("""
        UPDATE table1
        SET 
        table1.column1 = table2.column1,
        table1.column2 = table2.column2
        FROM table2
        WHERE table1.id = table2.id""")

Answer 1

You can try this option:

column_names = ['column1', 'column2']

sql_cmd = (""" UPDATE table1 SET table1.{} = table2.{}, 
                                 table1.{} = table2.{}
                FROM table2 WHERE table1.id = table2.id""").format(column_names[0], column_names[0], column_names[1], column_names[1])

print(sql_cmd)

Sample Jinja2 Code using Macro:

{% macro macro_join_condition(tab_prefix_1, tab_prefix_2, columns) %}
  {% for col in columns %}
    {% if loop.first %}
      {{ tab_prefix_1 }}{{ col }} = {{ tab_prefix_2 }}{{ col }}
    {% else %}
      and {{ tab_prefix_1 }}{{ col }} = {{ tab_prefix_2 }}{{ col }}
    {% endif %}
  {% endfor %}
{% endmacro %}

select *
from source_data sd right join target_data td on {{ macro_join_condition('td.','sd.', params.primaryKeyList) }}