utils.py 文件源码

def find_prev_keyword(sql, n_skip=0):
    """
    Find the last sql keyword in an SQL statement.

    Returns the value of the last keyword, and the text of the query with
    everything after the last keyword stripped.
    """
    if not sql.strip():
        return None, ''

    parsed = sqlparse.parse(sql)[0]
    flattened = list(parsed.flatten())
    flattened = flattened[:len(flattened) - n_skip]

    logical_operators = ('AND', 'OR', 'NOT', 'BETWEEN')

    for t in reversed(flattened):
        if t.value == '(' or (t.is_keyword and (
                              t.value.upper() not in logical_operators)):
            # Find the location of token t in the original parsed statement
            # We can't use parsed.token_index(t) because t may be a child token
            # inside a TokenList, in which case token_index thows an error
            # Minimal example:
            #   p = sqlparse.parse('select * from foo where bar')
            #   t = list(p.flatten())[-3]  # The "Where" token
            #   p.token_index(t)  # Throws ValueError: not in list
            idx = flattened.index(t)

            # Combine the string values of all tokens in the original list
            # up to and including the target keyword token t, to produce a
            # query string with everything after the keyword token removed
            text = ''.join(tok.value for tok in flattened[:idx + 1])
            return t, text

    return None, ''


# Postgresql dollar quote signs look like `$$` or `$tag$`