ORA-00920: invalid relational operator i obtain that please help me : INSERT INTO DIM_TEMPS (ID_DATE, DATE_DU_JOUR, ANNEE_CALENDAIRE, SEMESTRE, LIBELLE_SEMESTRE, TRIMESTRE, LIBELLE_TRIMESTRE, ANNEE_MOIS,MOIS, LIBELLE_MOIS, SEMAINE, JOUR, LIBELLE_JOUR, JOUR_FERIE, JOUR_OUVRE, QUANTIEME_JOUR) SELECT     TO_NUMBER(TO_CHAR(DT_CAL, "YYYYMMDD")) AS ID_CALENDRIER,     DT_CAL AS DATE_DU_JOUR,     TO_NUMBER(TO_CHAR(DT_CAL, "YYYY")) AS ANNEE_CALENDAIRE,     ROUND(TO_NUMBER(TO_CHAR(DT_CAL, "Q"))/2) AS SEMESTRE,     CASE ROUND(TO_NUMBER(TO_CHAR(DT_CAL, "Q"))/2) WHEN 1 THEN "1er semestre" ELSE "2ème semestre" END AS LIBELLE_SEMESTRE,     TO_NUMBER(TO_CHAR(DT_CAL, "Q")) AS TRIMESTRE,     CASE TO_NUMBER(TO_CHAR(DT_CAL, "Q")) WHEN 1 THEN "1er trimestre" ELSE TO_NUMBER(TO_CHAR(DT_CAL, "Q")) || "ème trimestre" END AS LIBELLE_TRIMESTRE,     TO_NUMBER(TO_NUMBER(TO_CHAR(DT_CAL, "YYYY")) || LPAD(TO_CHAR(DT_CAL, "MM"), 2, "0")) AS ANNEE_MOIS,     TO_NUMBER(TO_CHAR(DT_CAL, "MM")) AS MOIS,     TO_CHAR(DT_CAL, "Month") AS LIBELLE_MOIS,     TO_NUMBER(TO_CHAR(DT_CAL, "IW")) AS SEMAINE,     TO_NUMBER(TO_CHAR(DT_CAL, "DD")) AS JOUR,     TO_CHAR(DT_CAL, "Day") AS LIBELLE_JOUR,     CASE WHEN TO_CHAR(DT_CAL, "D") IN ("6", "7") THEN "Oui" ELSE "Non" END AS JOUR_FERIE,     CASE WHEN TO_CHAR(DT_CAL, "D") IN ("6", "7") THEN "Non" ELSE "Oui" END AS JOUR_OUVRE,     NUM_JOUR AS QUANTIEME_JOUR FROM (     SELECT to_date("19000101","YYYYMMDD") + (rownum - 1) AS DT_CAL, rownum AS NUM_JOUR     FROM dual     connect BY to_date("19000101","YYYYMMDD") + (rownum - 1) &lt;= to_date(&#039;29991231&#039;,&#039;YYYYMMDD&#039;) ); COMMIT;  