How many flights were there from San Diego International airport to Los Angeles International airport in the August of 2018?
flights from refers to ORIGIN; San Diego International airport refers to Description = 'San Diego, CA: San Diego International'; flights to refers to DEST; Los Angeles International airport refers to Description = 'Los Angeles, CA: Los Angeles International'; in the August of 2018 refers to FL_DATE like '2018/8%';
SELECT COUNT(FL_DATE) FROM Airlines WHERE FL_DATE LIKE '2018/8%' AND ORIGIN = ( SELECT T2.ORIGIN FROM Airports AS T1 INNER JOIN Airlines AS T2 ON T1.Code = T2.ORIGIN WHERE T1.Description = 'San Diego, CA: San Diego International' ) AND DEST = ( SELECT T4.DEST FROM Airports AS T3 INNER JOIN Airlines AS T4 ON T3.Code = T4.DEST WHERE T3.Description = 'Los Angeles, CA: Los Angeles International' )
CREATE TABLE IF NOT EXISTS "Air Carriers"
(
    Code        INTEGER
            primary key,
    Description TEXT
);
CREATE TABLE Airports
(
    Code        TEXT
            primary key,
    Description TEXT
);
CREATE TABLE Airlines
(
    FL_DATE               TEXT,
    OP_CARRIER_AIRLINE_ID INTEGER,
    TAIL_NUM              TEXT,
    OP_CARRIER_FL_NUM     INTEGER,
    ORIGIN_AIRPORT_ID     INTEGER,
    ORIGIN_AIRPORT_SEQ_ID INTEGER,
    ORIGIN_CITY_MARKET_ID INTEGER,
    ORIGIN                TEXT,
    DEST_AIRPORT_ID       INTEGER,
    DEST_AIRPORT_SEQ_ID   INTEGER,
    DEST_CITY_MARKET_ID   INTEGER,
    DEST                  TEXT,
    CRS_DEP_TIME          INTEGER,
    DEP_TIME              INTEGER,
    DEP_DELAY             INTEGER,
    DEP_DELAY_NEW         INTEGER,
    ARR_TIME              INTEGER,
    ARR_DELAY             INTEGER,
    ARR_DELAY_NEW         INTEGER,
    CANCELLED             INTEGER,
    CANCELLATION_CODE     TEXT,
    CRS_ELAPSED_TIME      INTEGER,
    ACTUAL_ELAPSED_TIME   INTEGER,
    CARRIER_DELAY         INTEGER,
    WEATHER_DELAY         INTEGER,
    NAS_DELAY             INTEGER,
    SECURITY_DELAY        INTEGER,
    LATE_AIRCRAFT_DELAY   INTEGER,
    FOREIGN KEY (ORIGIN) REFERENCES Airports(Code),
    FOREIGN KEY (DEST) REFERENCES Airports(Code),
    FOREIGN KEY (OP_CARRIER_AIRLINE_ID) REFERENCES "Air Carriers"(Code)
);
